Here are some File-Handling Questions and Answers:-
Question 1:Write a program in C to create and store information in a text file.
Solution:
#include <stdio.h>
#include <stdlib.h>
int main()
{
char str[1000];
FILE *fptr;
char fname[20] = "test.txt";
printf("\n\n Create a file (test.txt) and input text :\n");
printf("----------------------------------------------\n");
fptr = fopen(fname, "w");
if (fptr == NULL)
{
printf(" Error in opening file!");
exit(1);
}
printf(" Input a sentence for the file : ");
fgets(str, sizeof str, stdin);
fprintf(fptr, "%s", str);
fclose(fptr);
printf("\n The file %s created successfully...!!\n\n", fname);
return 0;
}
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Question 2:Write a program in C to read an existing file.
Solution:
#include <stdio.h>
#include <stdlib.h>
void main()
{
FILE *fptr;
char fname[20];
char str;
printf("\n\n Read an existing file :\n");
printf("------------------------------\n");
printf(" Input the filename to be opened : ");
scanf("%s",fname);
fptr = fopen (fname, "r");
if (fptr == NULL)
{
printf(" File does not exist or cannot be opened.\n");
exit(0);
}
printf("\n The content of the file %s is :\n",fname);
str = fgetc(fptr);
while (str != EOF)
{
printf ("%c", str);
str = fgetc(fptr);
}
fclose(fptr);
printf("\n\n");
}
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Question 3:Write a program in C to write multiple lines in a text file.
Solution:
#include <stdio.h>
int main ()
{
FILE * fptr;
int i,n;
char str[100];
char fname[20]="test.txt";
char str1;
printf("\n\n Write multiple lines in a text file and read the file :\n");
printf("------------------------------------------------------------\n");
printf(" Input the number of lines to be written : ");
scanf("%d", &n);
printf("\n :: The lines are ::\n");
fptr = fopen (fname,"w");
for(i = 0; i < n+1;i++)
{
fgets(str, sizeof str, stdin);
fputs(str, fptr);
}
fclose (fptr);
/*-------------- read the file -------------------------------------*/
fptr = fopen (fname, "r");
printf("\n The content of the file %s is :\n",fname);
str1 = fgetc(fptr);
while (str1 != EOF)
{
printf ("%c", str1);
str1 = fgetc(fptr);
}
printf("\n\n");
fclose (fptr);
return 0;
}
You can check the solution:- Check here
Question 4:Write a program in C to count a number of words and characters in a file.
Solution:
#include <stdio.h>
#include <stdlib.h>
void main()
{
FILE *fptr;
char ch;
int wrd=1,charctr=1;
char fname[20];
printf("\n\n Count the number of words and characters in a file :\n");
printf("---------------------------------------------------------\n");
printf(" Input the filename to be opened : ");
scanf("%s",fname);
fptr=fopen(fname,"r");
if(fptr==NULL)
{
printf(" File does not exist or can not be opened.");
}
else
{
ch=fgetc(fptr);
printf(" The content of the file %s are : ",fname);
while(ch!=EOF)
{
printf("%c",ch);
if(ch==' '||ch=='\n')
{
wrd++;
}
else
{
charctr++;
}
ch=fgetc(fptr);
}
printf("\n The number of words in the file %s are : %d\n",fname,wrd-2);
printf(" The number of characters in the file %s are : %d\n\n",fname,charctr-1);
}
fclose(fptr);
}
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Question 5:Write a program in C to delete a specific line from a file.
Solution:
#include <stdio.h>
#include <string.h>
#define MAX 256
int main()
{
int lno, ctr = 0;
char ch;
FILE *fptr1, *fptr2;
char fname[MAX];
char str[MAX], temp[] = "temp.txt";
printf("\n\n Delete a specific line from a file :\n");
printf("-----------------------------------------\n");
printf(" Input the file name to be opened : ");
scanf("%s",fname);
fptr1 = fopen(fname, "r");
if (!fptr1)
{
printf(" File not found or unable to open the input file!!\n");
return 0;
}
fptr2 = fopen(temp, "w"); // open the temporary file in write mode
if (!fptr2)
{
printf("Unable to open a temporary file to write!!\n");
fclose(fptr1);
return 0;
}
printf(" Input the line you want to remove : ");
scanf("%d", &lno);
lno++;
// copy all contents to the temporary file except the specific line
while (!feof(fptr1))
{
strcpy(str, "\0");
fgets(str, MAX, fptr1);
if (!feof(fptr1))
{
ctr++;
/* skip the line at given line number */
if (ctr != lno)
{
fprintf(fptr2, "%s", str);
}
}
}
fclose(fptr1);
fclose(fptr2);
remove(fname); // remove the original file
rename(temp, fname); // rename the temporary file to original name
/*------ Read the file ----------------*/
fptr1=fopen(fname,"r");
ch=fgetc(fptr1);
printf(" Now the content of the file %s is : \n",fname);
while(ch!=EOF)
{
printf("%c",ch);
ch=fgetc(fptr1);
}
fclose(fptr1);
/*------- End of reading ---------------*/
return 0;
}
You can check the solution:- Check here
Question 6:Write a program in C to replace a specific line with another text in a file.
Solution:
#include <stdio.h>
#include <string.h>
#define MAX 256
int main()
{
FILE *fptr1, *fptr2;
int lno, linectr = 0;
char str[MAX],fname[MAX];
char newln[MAX], temp[] = "temp.txt";
printf("\n\n Replace a specific line in a text file with a new text :\n");
printf("-------------------------------------------------------------\n");
printf(" Input the file name to be opened : ");
fgets(fname, MAX, stdin);
fname[strlen(fname) - 1] = '\0';
fptr1 = fopen(fname, "r");
if (!fptr1)
{
printf("Unable to open the input file!!\n");
return 0;
}
fptr2 = fopen(temp, "w");
if (!fptr2)
{
printf("Unable to open a temporary file to write!!\n");
fclose(fptr1);
return 0;
}
/* get the new line from the user */
printf(" Input the content of the new line : ");
fgets(newln, MAX, stdin);
/* get the line number to delete the specific line */
printf(" Input the line no you want to replace : ");
scanf("%d", &lno);
lno++;
// copy all contents to the temporary file other except specific line
while (!feof(fptr1))
{
strcpy(str, "\0");
fgets(str, MAX, fptr1);
if (!feof(fptr1))
{
linectr++;
if (linectr != lno)
{
fprintf(fptr2, "%s", str);
}
else
{
fprintf(fptr2, "%s", newln);
}
}
}
fclose(fptr1);
fclose(fptr2);
remove(fname);
rename(temp, fname);
printf(" Replacement did successfully..!! \n");
return 0;
}
You can check the solution:- Check here
Question 7: Write a program in C to append multiple lines at the end of a text file.
Solution:
#include <stdio.h>
int main ()
{
FILE * fptr;
int i,n;
char str[100];
char fname[20];
char str1;
printf("\n\n Append multiple lines at the end of a text file :\n");
printf("------------------------------------------------------\n");
printf(" Input the file name to be opened : ");
scanf("%s",fname);
fptr = fopen(fname, "a");
printf(" Input the number of lines to be written : ");
scanf("%d", &n);
printf(" The lines are : \n");
for(i = 0; i < n+1;i++)
{
fgets(str, sizeof str, stdin);
fputs(str, fptr);
}
fclose (fptr);
//----- Read the file after appended -------
fptr = fopen (fname, "r");
printf("\n The content of the file %s is :\n",fname);
str1 = fgetc(fptr);
while (str1 != EOF)
{
printf ("%c", str1);
str1 = fgetc(fptr);
}
printf("\n\n");
fclose (fptr);
//------- End of reading ------------------
return 0;
}
You can check the solution:- Check here
Question 8:Write a program in C to copy a file in another name.
Solution:
#include <stdio.h>
#include <stdlib.h>
void main()
{
FILE *fptr1, *fptr2;
char ch, fname1[20], fname2[20];
printf("\n\n Copy a file in another name :\n");
printf("----------------------------------\n");
printf(" Input the source file name : ");
scanf("%s",fname1);
fptr1=fopen(fname1, "r");
if(fptr1==NULL)
{
printf(" File does not found or error in opening.!!");
exit(1);
}
printf(" Input the new file name : ");
scanf("%s",fname2);
fptr2=fopen(fname2, "w");
if(fptr2==NULL)
{
printf(" File does not found or error in opening.!!");
fclose(fptr1);
exit(2);
}
while(1)
{
ch=fgetc(fptr1);
if(ch==EOF)
{
break;
}
else
{
fputc(ch, fptr2);
}
}
printf(" The file %s copied successfully in the file %s. \n\n",fname1,fname2);
fclose(fptr1);
fclose(fptr2);
getchar();
}
You can check the solution:- Check here
Question 9:Write a program in C to merge two files and write it in a new file
Solution:
#include <stdio.h>
#include <stdlib.h>
void main()
{
FILE *fold1, *fold2, *fnew;
char ch, fname1[20], fname2[20], fname3[30];
printf("\n\n Merge two files and write it in a new file :\n");
printf("-------------------------------------------------\n");
printf(" Input the 1st file name : ");
scanf("%s",fname1);
printf(" Input the 2nd file name : ");
scanf("%s",fname2);
printf(" Input the new file name where to merge the above two files : ");
scanf("%s",fname3);
fold1=fopen(fname1, "r");
fold2=fopen(fname2, "r");
if(fold1==NULL || fold2==NULL)
{
//perror("Error Message ");
printf(" File does not exist or error in opening...!!\n");
exit(EXIT_FAILURE);
}
fnew=fopen(fname3, "w");
if(fnew==NULL)
{
//perror("Error Message ");
printf(" File does not exist or error in opening...!!\n");
exit(EXIT_FAILURE);
}
while((ch=fgetc(fold1))!=EOF)
{
fputc(ch, fnew);
}
while((ch=fgetc(fold2))!=EOF)
{
fputc(ch, fnew);
}
printf(" The two files merged into %s file successfully..!!\n\n", fname3);
fclose(fold1);
fclose(fold2);
fclose(fnew);
}
You can check the solution:- Check here
Question 10:Write a program in C to encrypt a text file.
Solution:
#include <stdio.h>
#include <stdlib.h>
void main()
{
char fname[20], ch;
FILE *fpts, *fptt;
printf("\n\n Encrypt a text file :\n");
printf("--------------------------\n");
printf(" Input the name of file to encrypt : ");
scanf("%s",fname);
fpts=fopen(fname, "r");
if(fpts==NULL)
{
printf(" File does not exists or error in opening..!!");
exit(1);
}
fptt=fopen("temp.txt", "w");
if(fptt==NULL)
{
printf(" Error in creation of file temp.txt ..!!");
fclose(fpts);
exit(2);
}
while(1)
{
ch=fgetc(fpts);
if(ch==EOF)
{
break;
}
else
{
ch=ch+100;
fputc(ch, fptt);
}
}
fclose(fpts);
fclose(fptt);
fpts=fopen(fname, "w");
if(fpts==NULL)
{
printf(" File does not exists or error in opening..!!");
exit(3);
}
fptt=fopen("temp.txt", "r");
if(fptt==NULL)
{
printf(" File does not exists or error in opening..!!");
fclose(fpts);
exit(4);
}
while(1)
{
ch=fgetc(fptt);
if(ch==EOF)
{
break;
}
else
{
fputc(ch, fpts);
}
}
printf(" File %s successfully encrypted ..!!\n\n", fname);
fclose(fpts);
fclose(fptt);
}
You can check the solution:- Check here
Question 11:Write a program in C to remove a file from the disk.
Solution:
#include <stdio.h>
void main()
{
int status;
char fname[20];
printf("\n\n Remove a file from the disk :\n");
printf("----------------------------------\n");
printf(" Input the name of file to delete : ");
scanf("%s",fname);
status=remove(fname);
if(status==0)
{
printf(" The file %s is deleted successfully..!!\n\n",fname);
}
else
{
printf(" Unable to delete file %s\n\n",fname);
}
}
You can check the solution:- Check here
**Important**
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| Code |
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| Code |
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| Input |
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| ODD-NUMBERS |
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| EVEN-NUMBERS |
#include <stdio.h>
#include <stdlib.h>
int main() {
char name[50];
char usn[10];
int usn_number;
int sem,i,n;
printf("Enter number of students: ");
scanf("%d",&n);
FILE *fptr;
fptr=(fopen("D:\\UniversityData.txt","w"));
if(fptr==NULL) {
printf("Error!");
exit(1);
}
for (i=0;i<n;++i) {
printf("For student%d\nEnter name: ",i+1);
scanf("%s",name);
printf("Enter University no.(After character give space): ");
scanf("%s%d",&usn,&usn_number);
printf("Enter Semester: ");
scanf("%d",&sem);
fprintf(fptr,"\n %s \t%s-%d \t%d \n",name,usn,usn_number,sem);
}
fclose(fptr);
return 0;
}
Note: Ensure that the folder ‘UniversityData’ is created in the D-drive and each field is separated by a tab space ie between name and usn or usn and semno.
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| Code |
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| Input Format |
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| Input Successfully saved in D: drive. |
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| Output |
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| Code |
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| Process |
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| Input File |
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| Output File |
2 Comments
You haven't used the command line arguments in question1 of important........ And according to question you have to use it in program.. :)
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