(a) Write a program to read a file and display contents with its line numbers.
Solution:
NOTE: Make a file as "DATA.TXT" in bin directory and write/paste some text in it, then run the program.
#include<stdio.h>
#include<conio.h>
void main() {
FILE *fp;
char i;
int line=1;
clrscr();
fp=fopen("DATA.TXT","r");
if(fp==NULL) {
printf("\n\nCannot open file!");
delay(1000);
exit();
}
printf("%2d. ",line); /* we already print 1st for the first line */
while(i!=EOF) {
i=fgetc(fp);
printf("%c",i);
/* if the character is newline,the line number will be\
printed after it */
if(i=='\n') {
line++;
printf("%2d. ",line);
}
}
fclose(fp);
getch();
}
---------------------------------------------------------------------------------------------------------------
(b) Write a program to find the size of a text file without traversing it character by character.
Solution:
NOTE: Make a file as "DATA.TXT" in bin directory and write/paste some text in it, then run the program.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main() {
FILE *fp;
char s[80],ch;
int len=0;
clrscr();
fp=fopen("data.txt","r");
while(fgets(s,79,fp)!=NULL)
len=len+strlen(s); /* length of each string */
/* spaces and newlines are also counted */
fclose(fp);
printf("length of file = %d",len);
getch();
}
----------------------------------------------------------------------------------------------------------------
(c) Write a program to add the contents of one file at the end of another.
Solution:
NOTE: Make two file as "FILE1.TXT" and "FILE2.TXT" in bin directory and then run the program. The contents of FILE1.TXT will be appended to FILE2.TXT.
#include<stdio.h>
#include<conio.h>
void main() {
FILE *f1,*f2;
char ch;
clrscr();
f1=fopen("FILE1.TXT","r"); /* file to append */
f2=fopen("FILE2.TXT","a+"); /* file to be appended */
if(f1==NULL || f2==NULL) {
printf("\ncannot open one of files!");
exit();
}
while(1) {
ch=fgetc(f1);
if(ch==EOF) {
break;
}
fputc(ch,f2);
}
fclose(f1);
fclose(f2);
printf("\ntask completed successfully!");
getch();
}
---------------------------------------------------------------------------------------------------------------
(d) Suppose a file contains student’s records with each record containing name and age of a student. Write a program to read these records and display them in sorted order by name.
Solution:
#include<stdio.h>
#include<conio.h>
#define N 100
struct student {
char name[30];
int age;
};
void main() {
struct student std;
struct student s[N]; /* size of array of structure defined globally for
convenience */
FILE *fp;
int flag=0,ch,i=0,count=0;
long recsize;
char another='y';
void srt_print(); /* funtion to sort and print */
clrscr();
recsize=sizeof(std);
fp=fopen("STUDENT.DAT","rb+");
if(fp==NULL) {
fp=fopen("STUDENT.DAT","wb+");
if(fp==NULL)
exit();
}
while(1) {
clrscr();
printf("\t\t\tStudent database\n");
printf("\t\t\t****************\n\n\n");
printf("\t\t\n1: Add student data\n");
printf("\t\t\n2: List student data\n");
printf("\t\t\n0: Exit");
gotoxy(2,24);
printf("Your choice: ");
scanf("%d",&ch);
switch(ch) {
case 1:
clrscr();
while(another=='y' || another=='Y') {
clrscr();
printf("\t\tAdd student data\n");
printf("\t\t****************\n\n");
printf("\nEnter student name: ");
scanf("%s",&std.name);
printf("\n\naEnter student age: ");
scanf("%d",&std.age);
fseek(fp,0,SEEK_END);
fwrite(&std,recsize,1,fp);
gotoxy(2,24);
printf("Add another information(Y/N): ");
fflush(stdin);
another=getche();
}
break;
case 2:
clrscr();
printf("\t\tList student data\n");
printf("\t\t*****************\n\n");
rewind(fp);
while(fread(&std,recsize,1,fp)==1) {
s[i]=std;
flag=1;
i++;
count++;
}
srt_print(&s,count); /* function to print names */
if(flag==0) {
printf("\n\n\nNo data found!\n");
}
printf("\n\n\npress any key to return...");
getch();
break;
case 0:
fclose(fp);
exit();
default:
printf("wrong input!\n");
exit();
}
}
}
/******** main ends ************/
/**** sorting and printing function ****/
void srt_print(struct student *ss, int n) {
struct student temp;
int i,j;
for(i=0;i<=n;i++) {
for(j=i+1;j<n;j++) {
/* checking first alphabets of both names */
if(ss[i].name[0] > ss[j].name[0]) {
temp=ss[i];
ss[i]=ss[j];
ss[j]=temp;
}
/* if first alphabets are same */
else if(ss[i].name[0]==ss[j].name[0] && ss[i].name[1] > ss[j].name[1]) {
temp=ss[i];
ss[i]=ss[j];
ss[j]=temp;
}
/* if first 2 alphabets are same */
else if(ss[i].name[0]==ss[j].name[0] && ss[i].name[1]==ss[j].name[1]) {
if(ss[i].name[2] > ss[j].name[2]) {
temp=ss[i];
ss[i]=ss[j];
ss[j]=temp;
}
}
/* if first 3 alphabets are same */
else if(ss[i].name[0]==ss[j].name[0] && ss[i].name[1]==ss[j].name[1]) {
if(ss[i].name[2]==ss[i].name[2]) {
if(ss[i].name[3] > ss[j].name[3]) {
temp=ss[i];
ss[i]=ss[j];
ss[j]=ss[i];
}
}
}
/* if first four 4 alphabets are same */
else if(ss[i].name[0]==ss[j].name[0] && ss[i].name[1]==ss[j].name[1]) {
if(ss[i].name[2]==ss[j].name[2] && ss[i].name[2]==ss[j].name[2]) {
if(ss[i].name[3]==ss[j].name[3]) {
if(ss[i].name[4] > ss[j].name[4]) {
temp=ss[i];
ss[i]=ss[j];
ss[j]=ss[i];
}
}
}
}
}
}
/* printing sorted list */
for(i=0;i<n;i++) {
printf("\n%10s\t\t%2d\n",ss[i].name,ss[i].age);
}
}
--------------------------------------------------------------------------------------------------------------
(e) Write a program to copy one file to another. While doing so replace all lowercase characters to their equivalent uppercase characters.
Solution:
NOTE: Make a file as "FILE.TXT" in bin directory and write/paste some text in it. then run the program and you will receive another file as "RESULT.TXT" with uppercase letters.
#include<stdio.h>
#include<conio.h>
void main() {
FILE *fr,*fw;
char a[1000];
char ch,upr;
clrscr();
fr=fopen("SOURCE.TXT","r");
if(fr==NULL) {
printf("cannot open source file!\n");
}
fw=fopen("RESULT.TXT","w");
if(fw==NULL) {
printf("cannot open target file!\n");
}
while(1) {
ch=fgetc(fr);
if(ch==EOF)
break;
else {
if(ch>=97 && ch<=122) {
ch=ch-32;
}
fputc(ch,fw);
}
}
fclose(fr);
fclose(fw);
printf("Task completed!");
getch();
}
----------------------------------------------------------------------------------------------------------------
(f) Write a program that merges lines alternately from two files and writes the results to new file. If one file has less number of lines than the other, the remaining lines from the larger file should be simply copied into the target file.
Solution:
----------------------------------------------------------------------------------------------------------------
(g) Write a program to display the contents of a text file on the screen. Make following provisions:
Display the contents inside a box drawn with opposite corner
co-ordinates being ( 0, 1 ) and ( 79, 23 ). Display the name of the file whose contents are being displayed, and the page numbers in the zeroth row. The moment one screenful of file has been displayed, flash a message ‘Press any key...’ in 24th row. When a key is hit, the next page’s contents should be displayed, and so on till the end of file.
Solution:
#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<types.h>
#include<stat.h>
#include<fcntl.h>
void box();
void print();
void main() {
int inhandle,bytes,pg=1;
FILE *fp;
char source[80],buffer[1400];
clrscr();
printf("Enter file name: ");
gets(source);
inhandle=open(source, O_RDONLY);
if(inhandle==-1) {
printf("cannot open file!");
exit();
}
clrscr();
while(1) {
bytes=read(inhandle,buffer,1387);
if(bytes>0) {
gotoxy(32,1); /* showing filename */
printf("%s",strupr(source));
gotoxy(70,1);
printf("Pg: %3d",pg); /* showing page number */
box(); /* passing the heading and page number to the function */
print(buffer); /* passing the buffer to the function */
}
else {
gotoxy(70,1);
printf("Pg: %3d",pg);
break;
}
++pg;
}
close(inhandle);
getch();
}
/********************************/
/* function to print the buffer */
/********************************/
void print(char s[1400]) {
int x=4,y=3,i=0;
while(s[i]!=EOF) {
gotoxy(x,y);
printf("%c",s[i]);
if(x>74) {
x=4;
y+=1;
}
if(y>21) {
gotoxy(2,24);
printf("press any key to go to next page...");
x=4;
y=3;
getch();
clrscr();
box();
}
x++;
i++;
}
}
/****************************/
/* function to draw the box */
/****************************/
void box() {
int i,j;
for(i=2;i<=77;i++) {
gotoxy(i,2);
printf("%c",196);
gotoxy(i,23);
printf("%c",196);
}
for(j=3;j<=22;j++) {
gotoxy(2,j);
printf("%c",179);
gotoxy(77,j);
printf("%c",179);
}
gotoxy(77,23);
printf("%c",217);
gotoxy(77,2);
printf("%c",191);
gotoxy(2,23);
printf("%c",192);
gotoxy(2,2);
printf("%c",218);
}
----------------------------------------------------------------------------------------------------------------
(h) Write a program to encrypt/decrypt a file using:
(1) An offset cipher: In an offset cipher each character from the source file is offset with a fixed value and then written to the target file.
For example, if character read from the source file is ‘A’, then convert this into a new character by offsetting ‘A’ by a fixed value, say 128, and then writing the new character to the target file.
(2) A substitution cipher: In this each character read from the source file is substituted by a corresponding predetermined character and this character is written to the target file.
For example, if character ‘A’ is read from the source file, and if we have decided that every ‘A’ is to be substituted by ‘!’, then a ‘!’ would be written to the target file in place of every ‘A’ Similarly, every ‘B’ would be substituted by ‘5’ and so on.
Solution:
Offset cipher Encryption:
#include<stdio.h>
#include<conio.h>
void main() { /* offset cipher encryption */
/* every character has been added to 128 and the new value has been
written */
FILE *fp,*ft;
char ch;
clrscr();
fp=fopen("data.txt","r");
ft=fopen("temp.txt","w");
if(fp==NULL) {
printf("cannot open one of files!");
exit();
}
while(1) {
ch=fgetc(fp);
if(ch==EOF)
break;
ch=ch+128; /* offset cipher encryption */
fputc(ch,ft);
}
fclose(fp);
fclose(ft);
remove("data.txt");
rename("temp.txt","data.txt");
printf("task completed!");
getch();
}
Offset cipher Decryption:
#include<stdio.h>
#include<conio.h>
void main() { /* offset cipher decryption */
FILE *fp,*ft;
char ch;
fp=fopen("data.txt","r");
ft=fopen("temp.txt","w");
if(fp==NULL) {
printf("cannot open one of files!");
exit();
}
while(1) {
ch=fgetc(fp);
if(ch==EOF)
break;
ch=ch-128; /* decryption */
fputc(ch,ft);
}
fclose(fp);
fclose(ft);
remove("data.txt");
rename("temp.txt","data.txt");
printf("task completed!");
getch();
}
Substitution cipher encryption:
#include<stdio.h>
#include<conio.h>
void main() { /* substitution cipher encryption */
/* all vowels have been exchanged with first five ascii characters and
every space has been converted to 6th ascii character */
FILE *fp,*ft;
char ch;
clrscr();
fp=fopen("data.txt","r");
ft=fopen("temp.txt","w");
if(fp==NULL) {
printf("cannot open one of files!");
exit();
}
while(1) {
ch=fgetc(fp);
if(ch==EOF)
break;
encrypt(&ch); /* function for encryption */
fputc(ch,ft);
}
fclose(fp);
fclose(ft);
remove("data.txt");
rename("temp.txt","data.txt");
printf("task completed!");
getch();
}
encrypt(char *c) {
if(*c=='a') {
*c='!';
}
if(*c=='e') {
*c='@';
}
if(*c=='i') {
*c='#';
}
if(*c=='o') {
*c='$';
}
if(*c=='u') {
*c='%';
}
if(*c==' ') {
*c='^';
}
return *c;
}
Substitution cipher Decryption:
#include<stdio.h>
#include<conio.h>
void main() {
/* substitution cipher's decryption */
FILE *fp,*ft;
char ch;
fp=fopen("data.txt","r");
ft=fopen("temp.txt","w");
if(fp==NULL) {
printf("cannot open one of files!");
exit();
}
while(1) {
ch=fgetc(fp);
if(ch==EOF)
break;
decrypt(&ch); /* function for decryption */
fputc(ch,ft);
}
fclose(fp);
fclose(ft);
remove("data.txt");
rename("temp.txt","data.txt");
printf("task completed!");
getch();
}
decrypt(char *c) {
if(*c=='!')
*c='a';
if(*c=='@')
*c='e';
if(*c=='#')
*c='i';
if(*c=='$')
*c='o';
if(*c=='%')
*c='u';
if(*c=='^')
*c=' ';
return *c;
}
----------------------------------------------------------------------------------------------------------------
(i) In the file ‘CUSTOMER.DAT’ there are 100 records with the following structure:
struct customer
{
int accno ;
char name[30] ;
float balance ;
} ;
In another file ‘TRANSACTIONS.DAT’ there are several records with the following structure:
struct trans
{
int accno ,
char trans_type ;
float amount ;
} ;
The parameter trans_type contains D/W indicating deposit or withdrawal of amount. Write a program to update ‘CUSTOMER.DAT’ file, i.e. if the trans_type is ‘D’ then update the balance of ‘CUSTOMER.DAT’ by adding amount to balance for the corresponding accno. Similarly, if trans_type is ‘W’ then subtract the amount from balance. However, while subtracting the amount make sure that the amount should not get overdrawn, i.e. at least 100 Rs. Should remain in the account.
Solution:
NOTE: If on withdrawal, the balance subtracts to less than 100. The withdrawal will not be performed.
#include<stdio.h>
#include<conio.h>
void main() {
struct customer {
int accno;
char name[30];
float balance;
}cust;
struct trans {
int accno;
char trans_type;
float amount;
}tra;
FILE *fp,*ft,*ftemp;
int flag=0;
long recsize,retsize;
char another,ch;
clrscr();
fp=fopen("CUSTOMER.DAT","rb+");
if(fp==NULL) {
fp=fopen("CUSTOMER.DAT","wb+");
if(fp==NULL)
printf("cannot open customer data file!\n");
exit();
}
ft=fopen("TRANSACTIONS.DAT","rb+");
if(ft==NULL) {
ft=fopen("TRANSACTIONS.DAT","wb+");
if(ft==NULL)
printf("cannot open transactions file!\n");
exit();
}
recsize=sizeof(cust);
retsize=sizeof(tra);
while(1) {
clrscr();
printf("\t\tCutomer Transactions:\n");
printf("\t\t*********************\n\n\n");
printf("\t1: Add customer information:\n\n");
printf("\t2: Add transaction information:\n\n");
printf("\t3: List customer information:\n\n");
printf("\t4: List transaction information:\n\n");
printf("\t5: Perform transaction:\n\n");
printf("\t0: Exit:\n\n\n");
gotoxy(2,24);
printf("Your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(fp,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
printf("\t\tAdd customer information:\n");
printf("\t\t*************************\n\n");
printf("\nEnter account number: ");
scanf("%d",&cust.accno);
printf("\n\nEnter name: ");
scanf("%s",cust.name);
printf("\n\nEnter balance: ");
fflush(stdin);
scanf("%f",&cust.balance);
fwrite(&cust,recsize,1,fp);
gotoxy(2,24);
printf("Add another customer information(Y/N): ");
another=getche();
clrscr();
}
break;
case '2':
clrscr();
fseek(ft,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
printf("\t\tAdd transaction information:\n");
printf("\t\t****************************\n\n\n");
printf("Enter existing customer account number: ");
scanf("%d",&tra.accno);
printf("\n\nEnter transaction type(D/W): ");
fflush(stdin);
scanf("%c",&tra.trans_type);
printf("\n\nEnter amount for transaction: ");
fflush(stdin);
scanf("%f",&tra.amount);
fwrite(&tra,retsize,1,ft);
gotoxy(2,24);
printf("Enter another information(Y/N): ");
another=getche();
clrscr();
}
break;
case '3':
clrscr();
printf("\t\tList customer information:\n");
printf("\t\t**************************\n\n");
rewind(fp);
while(fread(&cust,recsize,1,fp)==1) {
printf("\n%5d\t%-8s\t%5.2f\n",cust.accno,cust.name,cust.balance);
flag=1;
}
if(flag==0) {
gotoxy(2,12);
printf("No customer information found!\n");
}
printf("\n\npress any key to go back...");
getch();
break;
case '4':
clrscr();
printf("\t\tList transaction information:\n");
printf("\t\t*****************************\n\n");
rewind(ft);
while(fread(&tra,retsize,1,ft)==1) {
printf("\n%5d\t%c\t%6.2f\n",tra.accno,tra.trans_type,tra.amount);
flag=1;
}
if(flag==0) {
gotoxy(2,12);
printf("No transaction information found!\n");
}
printf("\n\npress any key to go back...");
getch();
break;
case '5':
clrscr();
printf("\t\tPerform transactions\n");
printf("\t\t********************\n\n");
rewind(fp);
while(fread(&cust,recsize,1,fp)==1) {
rewind(ft);
while(fread(&tra,retsize,1,ft)==1) {
if(cust.accno==tra.accno) {
flag=1;
if(tra.trans_type=='D' || tra.trans_type=='d') {
cust.balance+=tra.amount;
fseek(fp,-recsize,SEEK_CUR);
fwrite(&cust,recsize,1,fp);
}
else if(tra.trans_type=='W' || tra.trans_type=='w') {
if((cust.balance-tra.amount)>=100) {
cust.balance-=tra.amount;
fseek(fp,-recsize,SEEK_CUR);
fwrite(&cust,recsize,1,fp);
}
}
}
}
}
fclose(ft);
ftemp=fopen("TEMP.DAT","rb+");
if(ftemp==NULL) {
ftemp=fopen("TEMP.DAT","wb+");
}
remove("TRANSACTIONS.DAT");
rename("TEMP.DAT","TRANSACTIONS.DAT");
ft=fopen("TRANSACTIONS.DAT","rb+");
if(ft==NULL) {
ft=fopen("TRANSACTIONS.DAT","wb+");
}
if(flag==0) {
gotoxy(2,12);
printf("No active transactions\n");
}
else if(flag>0) {
gotoxy(2,12);
printf("Transactions performed seccussfully!\n");
gotoxy(2,14);
printf("NOTE: withdrawl for low balance accounts has not been performed\n");
}
gotoxy(2,24);
printf("press any key to return...");
getch();
break;
case '0':
fclose(fp);
fclose(ft);
exit();
}
}
}
---------------------------------------------------------------------------------------------------------------
(j) There are 100 records present in a file with the following structure:
struct date
{
int d, m, y ;
} ;
struct employee
{
int empcode[6] ;
char empname[20] ;
struct date join_date ;
float salary ;
} ;
Write a program to read these records, arrange them in ascending order of join_date and write them in to a target file.
Solution:
----------------------------------------------------------------------------------------------------------------
(k) A hospital keeps a file of blood donors in which each record has the format:
Name: 20 Columns
Address: 40 Column
Age: 2 Columns
Blood Type: 1 Column (Type 1, 2, 3 or 4)
Write a program to read the file and print a list of all blood donors whose age is below 25 and blood is type 2.
Solution:
Program to creat record file of blood donors
/* This program will make a file of blood donors and save information in it */
/* Writing program */
#include<stdio.h>
#include<conio.h>
void main() {
FILE *fp;
char another='y';
struct blood {
char name[50];
char adr[50];
int age;
int bld;
} b;
clrscr();
fp=fopen("BLOODBANK.DAT","wb");
if(fp==NULL) {
printf("cannot open target file!\n");
exit();
}
while(another=='Y' || another=='y') {
clrscr();
printf("\t\tInformation of Blood donor\n");
printf("\t\t**************************\n\n\n");
printf("Enter the name: ");
scanf("%s",b.name);
printf("\n\nenter the address: ");
scanf("%s",b.adr);
printf("\n\nenter the age: ");
scanf("%d",&b.age);
printf("\n\nenter the blood group(1/2/3/4): ");
scanf("%d",&b.bld);
fprintf(fp,"%s\t%s\t%d\t%d",b.name,b.adr,b.age,b.bld);
printf("\n\n\nenter more information(Y/N): ");
fflush(stdin);
another=getch();
}
fclose(fp);
}
Program to read record file for specifications
/* This program will read the information from the file made by writing program */
/* Reading Program */
#include<stdio.h>
#include<conio.h>
void main() {
FILE *fp;
char ch;
struct blood {
char name[50];
char adr[50];
int age;
int bld;
}b;
clrscr();
fp=fopen("BLOODBANK.DAT","rb");
if(fp==NULL) {
printf("cannot open source file!\n\n");
exit();
}
while(fscanf(fp,"%s\t%s\t%d\t%d",&b.name,&b.adr,&b.age,&b.bld)!=EOF)
if(b.age<25 && b.bld==2) {
printf("\n%s\t %s\t%2d\t %d",b.name,b.adr,b.age,b.bld);
}
fclose(fp);
getch();
}
----------------------------------------------------------------------------------------------------------------
(l) Given a list of names of students in a class, write a program to store the names in a file on disk. Make a provision to display the nth name in the list (n is data to be read) and to display all names starting with S.
Solution:
#include<stdio.h>
#include<conio.h>
void main() {
struct name {
int sn;
char name[30];
}s;
int i,num,flag=0;
long recsize;
char another,ch;
FILE *fp;
clrscr();
fp=fopen("NAMES.DAT","rb+");
if(fp==NULL) {
fp=fopen("NAMES.DAT","wb+");
if(fp==NULL)
printf("cannot open file! \n");
exit();
}
recsize=sizeof(s);
while(1) {
clrscr();
printf("\t\tStudent Names:\n");
printf("\t\t**************\n\n\n");
printf("\t1: Add names of students:\n\n");
printf("\t2: Search a student name:\n\n");
printf("\t3: List all student names:\n\n");
printf("\t4: List all names starting with 'S':\n\n");
printf("\t0: Exit\n\n");
gotoxy(2,24);
printf("Your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(fp,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
printf("\t\tAdd names of students:\n");
printf("\t\t**********************\n\n");
printf("Enter student number: ");
scanf("%d",&s.sn);
printf("\n\nEnter student name: ");
scanf("%s",s.name);
fwrite(&s,recsize,1,fp);
gotoxy(2,24);
printf("Enter another name(Y/N): ");
fflush(stdin);
another=getche();
clrscr();
}
break;
case '2':
clrscr();
printf("\t\tSearch a student name:\n");
printf("\t\t**********************\n\n");
printf("Enter student number: ");
scanf("%d",&num);
rewind(fp);
while(fread(&s,recsize,1,fp)==1) {
if(s.sn==num) {
printf("\n\nStudent Number: %5d\n\n",s.sn);
printf("Student name: %s\n\n",s.name);
flag=1;
break;
}
}
if(flag==0) {
printf("\n\n\nNo such name found!\n");
}
gotoxy(2,24);
printf("press any key to return...\n");
getch();
break;
case '3':
clrscr();
printf("\t\tList all student names\n");
printf("\t\t**********************\n\n\n");
rewind(fp);
while(fread(&s,recsize,1,fp)==1) {
printf("\n%5d\t%-10s\n",s.sn,s.name);
flag=1;
}
if(flag==0) {
printf("\n\n\nNo name found!\n");
}
printf("\n\n\npress any key to return...\n");
getch();
break;
case '4':
clrscr();
printf("\t\tAll name starting with 'S':\n");
printf("\t\t***************************\n\n\n");
rewind(fp);
while(fread(&s,recsize,1,fp)==1) {
if(strncmp('s',s.name[0])==0) { /* comparing only first character of \
name if it is "s" */
printf("\n%5d\t%-10s\n",s.sn,s.name);
flag=1;
}
}
if(flag==0) {
printf("\n\n\nNo name starting with \'S\' found!\n");
}
printf("\n\n\npress any key to return...\n");
getch();
break;
case '0':
fclose(fp);
exit();
}
}
}
----------------------------------------------------------------------------------------------------------------
(m) Assume that a Master file contains two fields, Roll no. and name of the student. At the end of the year, a set of students join the class and another set leaves. A Transaction file contains the roll numbers and an appropriate code to add or delete a student.
Write a program to create another file that contains the updated list of names and roll numbers. Assume that the Master file and the Transaction file are arranged in ascending order by roll numbers. The updated file should also be in ascending order by roll numbers.
Solution:
Note:- This program ( all the 3 ) are ideally for single. After you have ran it once, check the results and delete the updated list file before running it again. Assign roll number in ascending orders by roll numbers. And process data according to ascending nature.
1- first program will let you save data in masterfile.
2- second program will let you add or delete data and will generate an updated list in text mode.
3- obtain the updated list and check it ( assuming you have processed data as instructed).
1. program to creat master file.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main() {
FILE *fp;
struct student {
int rl;
char name[50];
}s;
char ch,another;
clrscr();
fp=fopen("MASTERFILE.DAT","rb+");
if(fp==NULL) {
fp=fopen("MASTERFILE.DAT","wb+");
if(fp==NULL)
puts("cannot open master file!");
exit();
}
while(1) {
clrscr();
gotoxy(30,2);
printf("Masterfile\n");
gotoxy(30,3);
printf("**********\n\n\n");
gotoxy(20,6);
printf("1: Enter student data: ");
gotoxy(20,8);
printf("2: Read student data: ");
gotoxy(20,10);
printf("0: Exit: ");
gotoxy(2,24);
printf("Your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(fp,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
clrscr();
gotoxy(2,24);
printf("NOTE: assign roll numbers in ascending order");
gotoxy(20,5);
printf("Enter roll number: ");
scanf("%d",&s.rl);
gotoxy(20,7);
printf("Enter name: ");
fflush(stdin);
gets(s.name);
fwrite(&s,sizeof(s),1,fp);
gotoxy(20,10);
printf("Add more data(Y/N): ");
fflush(stdin);
another=getche();
}
break;
case '2':
clrscr();
gotoxy(30,2);
printf("Student data");
gotoxy(30,3);
printf("************\n\n");
rewind(fp);
while(fread(&s,sizeof(s),1,fp)==1) {
printf("\n%d\t%s\n",s.rl,s.name);
}
printf("\n\npress any key to return...");
getch();
break;
case '0':
fclose(fp);
exit();
}
}
}
2. program to creat transaction file and generate updated list
#include<stdio.h>
#include<conio.h>
#include<string.h>
#define N 100
void main() {
FILE *ft,*fu,*fm,*ftemp;
struct student {
int rl;
char name[50];
}s,ss[N],temp;
struct transaction {
char stats;
int rl;
char name[50];
}t;
int flag=0;
char ch,another;
clrscr();
fm=fopen("MASTERFILE.DAT","rb+");
if(fm==NULL) {
printf("Masterfile doesn't exist!");
}
ft=fopen("TRANSACTION.DAT","rb+");
if(ft==NULL) {
ft=fopen("TRANSACTION.DAT","wb+");
if(ft==NULL)
puts("cannot open transactions file!");
exit();
}
fu=fopen("UPDATELIST.TXT","w+");
if(fu==NULL) {
puts("cannot open target file!");
exit();
}
while(1) {
clrscr();
gotoxy(30,2);
printf("Transaction-File\n");
gotoxy(30,3);
printf("****************\n\n\n");
gotoxy(20,6);
printf("1: ADD/DELETE student data from master list: ");
gotoxy(20,8);
printf("2: Read transaction data: ");
gotoxy(20,10);
printf("3: Creat updated list: ");
gotoxy(20,12);
printf("0: Exit:");
gotoxy(2,24);
printf("Your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(ft,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
clrscr();
gotoxy(2,23);
printf("NOTE: data to be deleted should match master list");
gotoxy(2,24);
printf("NOTE: data to be added should follow the ascending nature of master list");
gotoxy(20,5);
printf("ADD/DELETE student(A/D): ");
scanf("%c",&t.stats);
gotoxy(20,7);
printf("Enter roll number: ");
scanf("%d",&t.rl);
gotoxy(20,9);
printf("Enter name: ");
fflush(stdin);
gets(t.name);
fwrite(&t,sizeof(t),1,ft);
gotoxy(20,12);
printf("Add more data(Y/N): ");
fflush(stdin);
another=getche();
}
break;
case '2':
clrscr();
gotoxy(30,2);
printf("Student data");
gotoxy(30,3);
printf("************\n\n");
rewind(ft);
while(fread(&t,sizeof(t),1,ft)==1) {
printf("\n");
if(t.stats=='a' || t.stats=='A') {
printf("ADD");
}
else {
printf("DELETE");
}
printf("\t%d\t%s\n",t.rl,t.name);
}
printf("\n\npress any key to return...");
getch();
break;
case '3':
clrscr();
gotoxy(30,2);
printf("make updated list");
gotoxy(30,3);
printf("*****************\n\n");
rewind(fm);
while(fread(&s,sizeof(s),1,fm)==1) {
flag=0;
rewind(ft);
while(fread(&t,sizeof(t),1,ft)==1) {
if(t.rl==s.rl ) {
if(t.stats=='d' || t.stats=='D') {
flag=1;
}
}
}
if(flag==0)
fprintf(fu,"\n%d\t%-s\n",s.rl,s.name);
}
rewind(ft);
while(fread(&t,sizeof(t),1,ft)==1) {
if(t.stats=='a' || t.stats=='A') {
fprintf(fu,"\n%d\t%-s\n",t.rl,t.name);
}
}
ftemp=fopen("TEMP.DAT","wb+");
fclose(ftemp);
fclose(ft);
remove("TRANSACTION.DAT");
rename("TEMP.DAT","TRANSACTION.DAT");
ft=fopen("TRANSACTION.DAT","rb+");
gotoxy(2,24);
printf("press any key to continue...");
getch();
break;
case '0':
fclose(fm);
fclose(ft);
fclose(fu);
exit();
}
}
}
-----------------------------------------------------------------------------------------------------------------
(n) In a small firm employee numbers are given in serial numerical order, that is 1, 2, 3, etc.
− Create a file of employee data with following information: employee number, name, sex, gross salary.
− If more employees join, append their data to the file.
− If an employee with serial number 25 (say) leaves, delete the record by making gross salary 0.
− If some employee’s gross salary increases, retrieve the record and update the salary.
Write a program to implement the above operations.
Solution:
#include<stdio.h>
#include<conio.h>
void main() {
struct emp {
int empno;
char name[30];
char sex;
float gs;
} e;
FILE *fp,*ft;
int long recsize;
int empn,flag=0;
float new_sal;
char another,ch;
clrscr();
recsize=sizeof(e);
fp=fopen("EMP.DAT","rb+");
if(fp==NULL) {
fp=fopen("EMP.DAT","wb+");
if(fp==NULL)
exit();
}
while(1) {
clrscr();
printf("\t\tEmployee database management\n");
printf("\t\t****************************\n");
printf("\n\n\t1: Add another employee: ");
printf("\n\n\t2: Add salary information of employee: ");
printf("\n\n\t3: List all records: ");
printf("\n\n\t4: Delete employee with 0 salary: ");
printf("\n\n\t0: Exit:");
gotoxy(2,24);
printf("your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(fp,0,SEEK_END); /* seeking cursor to reach at the end of file */
another='Y';
while(another=='Y' || another=='y') {
printf("\n\tEnter new employee information\n");
printf("\t******************************\n\n\n");
printf("\nEnter employee number: ");
scanf("%d",&e.empno);
printf("\n\nEnter employee name: ");
scanf("%s",e.name);
printf("\n\nEnter sex(M/F/O): ");
scanf(" %c",&e.sex);
printf("\n\nEnter gross salary: ");
scanf("%f",&e.gs);
/* writing new information at the end of file */
fwrite(&e,recsize,1,fp);
printf("\n\n\n\nAdd another employee(Y/N): ");
fflush(stdin);
another=getche();
clrscr();
}
break;
case '2':
clrscr();
another='Y';
while(another=='Y' || another=='y') {
printf("\n\tEnter salary information\n");
printf("\t************************\n\n");
gotoxy(2,23); /* showing message at the bottom of the screen */
printf("NOTE: to delete an employee, mark his/her salary 0\n");
printf(" then use option 4 from main menu.");
gotoxy(3,5); /* returning cursor back from the bottom */
printf("Enter employee number: ");
scanf("%d",&empn); /* asking for employee number to search */
rewind(fp);
while(fread(&e,recsize,1,fp)==1) {
if(e.empno-empn==0) { /* if employee number matches with structure */
flag=1; /* condition indicator for printing further messages */
printf("\n\nEnter new salary for employee: ");
scanf("%f",&e.gs);
e.empno=e.empno; /* rest information should be same except only\
salary */
e.sex=e.sex;
e.name[30]=e.name[30];
fseek(fp,-recsize,SEEK_CUR); /* seeking the correct location of data within\
structure in the file */
fwrite(&e,recsize,1,fp); /* writing data at correct position */
break;
}
}
if(flag==0) /* conditional indicator used above */
printf("\n\n\n\tinformation does not exist!\n");
printf("\n\nenter another information(Y/N): ");
another=getche();
clrscr();
}
break;
case '4':
clrscr();
printf("\n\n\tDelete employee\n");
printf("\t***************\n\n");
ft=fopen("TEMP.DAT","w"); /* opening new temporary file */
rewind(fp); /* taking cursor back to the very beginning of file */
while(fread(&e,recsize,1,fp)==1) { /* matching each salary */
if(e.gs!=0.0 || e.gs!=0) { /* if salary is not 0 then data will be written to new
file */
flag=1;
fwrite(&e,recsize,1,ft);
}
}
fclose(fp);
fclose(ft);
remove("EMP.DAT"); /* removing original file with 0 salary and renaming\
temporary without 0 salary as the original file */
rename("TEMP.DAT","EMP.DAT");
fp=fopen("EMP.DAT","rt+"); /* opening the new file, it opens because it has
not been opened before */
/* a file cannot be opened twice during
execution as you know */
if(flag>0) {
printf("\n\n\nall records with 0 gross salary have been deleted. \n");
}
gotoxy(2,24);
printf("\n\n\npress any key to return...");
getch();
break;
case '0':
fclose(fp);
exit();
case '3':
clrscr();
printf("\t\tList all employees\n");
printf("\t\t******************\n\n\n");
rewind(fp);
while(fread(&e,recsize,1,fp)==1) {
flag=1;
printf("%2d\t%6s\t%c\t%.2f\n\n",e.empno,e.name,e.sex,e.gs);
}
if(flag==0)
printf("\n\n\tNo records exist!\n\n");
printf("\n\npress any key to return... ");
getch(); /* this is very important place, if we don't stop screen here \
after reading and printing the list,we won't be able to see it
and it will disappear and will return to main menu because
of "break" statement. */
break;
}
}
}
linkfloat() { /* function to avoid possible errors because of floats */
float a=0,*b;
b=&a;
a=*b;
return 0;
}
-----------------------------------------------------------------------------------------------------------------
(o) Given a text file, write a program to create another text file deleting the words “a”, “the”, “an” and replacing each one of them with a blank space.
Solution:
NOTE: Make a file "FILE.TXT" in bin directory and write/paste something in it, then run the program, you will get another file as "NEW.TXT" as result of the program.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void replace();
void main() {
FILE *fp,*ft;
char str[80],target[80];
clrscr();
fp=fopen("FILE.TXT","r");
if(fp==NULL) {
puts("cannot open source file!");
exit();
}
ft=fopen("NEW.TXT","w");
if(ft==NULL) {
puts("cannot open target file!");
exit();
}
while(fgets(str,79,fp)!=NULL) {
replace(str,&target);
fputs(target,ft);
}
fclose(fp);
fclose(ft);
printf("\nTask completed!");
getch();
}
void replace(char *s, char *s1) {
int i=0,j=0,k=0;
char temp[100],temp2[100],main[100],*t=temp,*m=main;
/* copying to temporary string */
while(*s!='\0') {
*t=*s;
t++;
s++;
}
*t='\0';
/**********************/
/* checking each word */
/**********************/
while(temp[i]!='\0') {
temp2[j]=temp[i];
if(temp[i]==' ') {
temp2[j]='\0';
if(strcmpi(temp2,"the")==0) {
strcpy(temp2," ");
}
else if(strcmpi(temp2,"an")==0) {
strcpy(temp2," ");
}
else if(strcmpi(temp2,"a")==0) {
strcpy(temp2," ");
}
j=0;
while(temp2[j]!='\0') {
main[k]=temp2[j];
k++;
j++;
}
main[k]=' '; /* adding space after each word is copied */
k++; /* increment so that the next word won't replace the space */
j=-1;
}
i++;
j++;
}
temp2[j]='\0'; /* last word terminated */
if(strcmpi(temp2,"the")==0){ /* checking last word too */
strcpy(temp2," ");
}
else if(strcmpi(temp2,"an")==0) {
strcpy(temp2," ");
}
else if(strcmpi(temp2,"a")==0) {
strcpy(temp2," ");
}
/***************************/
/* last word of the string */
/***************************/
else {
j=0;
while(temp2[j]!='\0') {
main[k]=temp2[j];
k++;
j++;
}
main[k]='\0'; /* new string is completely ready */
}
while(*m!='\0') {
*s1=*m;
s1++;
m++;
}
*s1='\0';
}
-----------------------------------------------------------------------------------------------------------------
(p) You are given a data file EMPLOYEE.DAT with the following record structure:
struct employee {
int empno ;
char name[30] ;
int basic, grade ;
} ;
Every employee has a unique empno and there are supposed to be no gaps between employee numbers. Records are entered into the data file in ascending order of employee number, empno. It is intended to check whether there are missing employee numbers. Write a program segment to read the data file records sequentially and display the list of missing employee numbers.
Solution:
NOTE: assign employee numbers in ascending order only.
#include<stdio.h>
#include<conio.h>
void main() {
struct employee {
int empno;
char name[30];
int basic,grade;
}e;
FILE *fp;
int num=0;
long recsize;
char another,ch;
clrscr();
fp=fopen("EMPLOYEE.DAT","rb+");
if(fp==NULL) {
fp=fopen("EMPLOYEE.DAT","wb+");
if(fp==NULL)
exit();
}
recsize=sizeof(e);
while(1) {
clrscr();
printf("\t\tEmployee number database:\n");
printf("\t\t*************************\n\n");
printf("\n\t1: Add employee information:\n");
printf("\n\t2: List employee information:\n");
printf("\n\t3: Check missing employee numbers:\n");
printf("\n\t0: Exit:\n\n");
gotoxy(2,24);
printf("your choice: ");
fflush(stdin);
ch=getche();
switch(ch) {
case '1':
clrscr();
fseek(fp,0,SEEK_END);
another='y';
while(another=='y' || another=='Y') {
printf("\t\tAdd employee information:\n");
printf("\t\t*************************\n\n");
printf("Note: employee numbers should be given in ascending order\n\n");
printf("\nEnter employee number: ");
scanf("%d",&e.empno);
printf("\n\nEnter employee name: ");
scanf("%s",e.name);
printf("\n\nEnter employee basic salary: ");
scanf("%d",&e.basic);
printf("\n\nEnter employee grade(1/2/3): ");
scanf("%d",&e.grade);
fwrite(&e,recsize,1,fp);
gotoxy(2,24);
printf("Add another employee information(Y/N): ");
fflush(stdin);
another=getche();
clrscr();
}
break;
case '2':
clrscr();
printf("\t\tList employee information:\n");
printf("\t\t**************************\n\n\n");
rewind(fp);
while(fread(&e,recsize,1,fp)==1) {
printf("\n%3d\t%8s\t%5d\t%d\n",e.empno,e.name,e.basic,e.grade);
}
printf("\n\npress any key to return...\n");
getch();
break;
case '3':
clrscr();
printf("\t\tMissing employee numbers:\n");
printf("\t\t*************************\n\n");
rewind(fp);
while(fread(&e,recsize,1,fp)==1) {
num=e.empno; /* assigning the value of first employee number */
break;
}
rewind(fp); /* again rewinding the file to read from beginning */
while(fread(&e,recsize,1,fp)==1) {
if(num!=e.empno) { /* if assigned number is smaller than employee number
we will print all the number between them */
while(num<e.empno) {
printf("%4d ",num);
num++;
}
num=e.empno+1;
}
/* we will assign greater value than employee number
to make sure that both don't match until another
greater employee number is found */
else
num=e.empno+1;
}
printf("\n\n press any key to return...");
getch();
break;
case '0':
fclose(fp);
exit();
}
}
}
-----------------------------------------------------------------------------------------------------------------
(q) Write a program to carry out the following:
− To read a text file “TRIAL.TXT” consisting of a maximum of 50 lines of text, each line with a maximum of 80 characters.
− Count and display the number of words contained in the file.
− Display the total number of four letter words in the text file.
Assume that the end of a word may be a space, comma or a full-stop followed by one or more spaces or a newline character.
Solution:
NOTE: Make a file "TRIAL.TXT" in bin directory and write something in it ,then run the program.
#include<stdio.h>
#include<conio.h>
void main() {
FILE *fp;
char s[80];
int twd,fwd,tw=0,fw=0;
void word();
clrscr();
fp=fopen("TRIAL.TXT","r");
if(fp==NULL) {
exit();
}
while(fgets(s,79,fp)!=NULL) {
word(s,&twd,&fwd);
tw=tw+twd;
fw=fw+fwd;
}
fclose(fp);
printf("\nTotal number of words in text file = %d\n",tw);
printf("\n\nTotal number of 4 letter words = %d\n",fw);
getch();
}
void word(char ss[80],int *tw, int *fw) {
int i=0,tot_wd=0,tot_4_wd=0;
while(ss[i]!='\0') {
/************************/
/* to cound total words */
/************************/
if(ss[i]>=65 && ss[i]<=90 || ss[i]>=97 && ss[i]<=122) {
if(ss[i+1]==' ' || ss[i+1]=='.' || ss[i+1]==',' || ss[i+1]=='\n' ) {
tot_wd++;
}
}
/*********************************/
/* to count total 4 letter words */
/*********************************/
if(ss[i]==' ' || ss[i]==',' || ss[i]=='.') {
if(ss[i+1]>=65 && ss[i+1]<=90 || ss[i+1]>=97 && ss[i+1]<=122) {
if(ss[i+2]>=65 && ss[i+2]<=90 || ss[i+2]>=97 && ss[i+2]<=122) {
if(ss[i+3]>=65 && ss[i+3]<=90 || ss[i+3]>=97 && ss[i+3]<=122) {
if(ss[i+4]>=65 && ss[i+4]<=90 || ss[i+4]>=97 && ss[i+4]<=122) {
if(ss[i+5]==' ' || ss[i+5]==',' || ss[i+5]=='.' || ss[i+5]=='\n') {
tot_4_wd++;
}
}
}
}
}
}
if(ss[i]>=65 && ss[i]<=90 || ss[i]>=97 && ss[i]<=122) {
if(ss[i+1]>=65 && ss[i+1]<=90 || ss[i+1]>=97 && ss[i+1]<=122) {
if(ss[i+2]>=65 && ss[i+2]<=90 || ss[i+2]>=97 && ss[i+2]<=122) {
if(ss[i+3]>=65 && ss[i+3]<=90 || ss[i+3]>=97 && ss[i+3]<=122) {
if(ss[i+4]==' ' || ss[i+4]==',' || ss[i+4]=='.' || ss[i+4]=='\n') {
}
}
}
}
}
i++;
}
*tw=tot_wd;
*fw=tot_4_wd;
}
-----------------------------------------------------------------------------------------------------------------
(r) Write a program to read a list of words, sort the words in alphabetical order and display them one word per line. Also give the total number of words in the list. Output format should be:
Total Number of words in the list is _______
Alphabetical listing of words is:
------
-----
Assume the end of the list is indicated by ZZZZZZ and there are maximum in 25 words in the Text file.
Solution:
NOTE: Make a file as "trial.txt" in bin directory and write some words in it. Words should be in the form of a list. One below another,then run the program.
#include<stdio.h>
#include<conio.h>
#define N 100
/* make a list of words, every words should be written under previous one to
make sure it's a list of words. */
/* upper case letters will be arranged before small case letter, so it is
recommended to use the list of either Capital letter or small case letters
but not both together. */
struct word {
char wrd [30];
};
void main() {
struct word w[N];
FILE *fp;
char s1[30];
int i=0,count=0;
void srt_wrd(); /* function to sort and print list */
clrscr();
fp=fopen("TRIAL.TXT","rb+");
while(fgets(s1,30,fp)!=NULL) {
strcpy(w[i].wrd,s1); /* copying each word in array of structure */
i++;
count++; /* count of all the words */
}
printf("Total words if file = %3d\n",count);
printf("\t\tList in alphabetical order:\n");
srt_wrd(&w,count); /* function for sorting and printing list */
fclose(fp);
getch();
}
void srt_wrd( struct word *w, int n) {
int i,j,k=0;
struct word temp;
/***************************************/
/* sorting words in alphabetical order */
/***************************************/
for(i=0;i<=n;i++) {
for(j=i+1;j<n;j++) {
/* testing the first alphabets of two words */
if(w[i].wrd[0] > w[j].wrd[0]) {
temp=w[i];
w[i]=w[j];
w[j]=temp;
}
/* testing the first two alphabets of two words */
else if(w[i].wrd[0]==w[j].wrd[0] && w[i].wrd[1] > w[j].wrd[1]) {
temp=w[i];
w[i]=w[j];
w[j]=temp;
}
/* testing first three alphabets of two words */
else if(w[i].wrd[0]==w[j].wrd[0] && w[i].wrd[1]==w[j].wrd[1]) {
if(w[i].wrd[2]>w[j].wrd[2]) {
temp=w[i];
w[i]=w[j];
w[j]=temp;
}
}
/* testing first four alphabets of two words */
else if(w[i].wrd[0]==w[j].wrd[0] && w[i].wrd[1]==w[j].wrd[1]) {
if(w[i].wrd[2]==w[j].wrd[2] && w[i].wrd[3]>w[j].wrd[2]) {
temp=w[i];
w[i]=w[j];
w[j]=temp;
}
}
}
}
/*****************************/
/* printing the sorted words */
/*****************************/
for(i=0;i<n;i++) {
printf("%-s\n",w[i].wrd);
k++;
if(k==10) {
printf("\n\npress any key to go to next page...");
getch();
k=1;
clrscr();
}
}
}
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(s) Write a program to carry out the following:
(a) Read a text file ‘INPUT.TXT’
(b) Print each word in reverse order
Example,
Input: INDIA IS MY COUNTRY
Output: AIDNI SI YM YRTNUOC
Assume that each word length is maximum of 10 characters and each word is separated by newline/blank characters.
Solution:
NOTE: Make a file "INPUT.TXT" in bin directory and write something in it, then run the program.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main() {
FILE *fs;
char s[80];
void rev();
clrscr();
fs=fopen("INPUT.TXT","r");
if(fs==NULL) {
printf("cannot open file!");
exit();
}
while(fgets(s,79,fs)!=NULL)
rev(s);
fclose(fs);
getch();
}
void rev(char s1[80]) {
char s2[80];
int i=0,j=0;
while(s1[i]!='\0') {
s2[j]=s1[i];
if(s1[i]==' ' || s1[i]=='\0') {
s2[j]='\0';
strrev(s2);
printf("%s ",s2);
j=-1;
}
i++;
j++;
}
s2[j]='\0';
printf("%s",strrev(s2));
}
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(s) Write a C program to read a large text file ‘NOTES.TXT’ and print it on the printer in cut-sheets, introducing page breaks at the end of every 50 lines and a pause message on the screen at the end of every page for the user to change the paper.