Question

Write a C program, called reverse, using standard I/O functions, to take a file as input then copies it to another file in reverse order. That is, the last byte becomes the first, the byte just before the last one becomes the second, etc. The program call should look like: reverse fileIn fileOut

Answer 1

C PROGRAM

#include<stdio.h>

// implement command line arguments
int main(int argc,char *argv[])
{
   FILE *fp1,*fp2; // create two file pointers
  
   int i=0,cnt; // declare integer variable i and cnt
  
   if(argc<3) // check arguments
   {
       // display this message and terminate
       printf("Error: Invalid Arguments");
       return -1;
   }
  
   fp1=fopen(argv[1],"r"); // open file of first argument in read mode
   fp2=fopen(argv[2],"w"); // open file of second argument in write mode
  
   if(fp1==NULL) // check the read file is not correct
   {
       // then, display this message and terminate
       printf("\n%s File can not be opend..\n",argv[1]);
       return -1;
   }
  
   fseek(fp1,0,SEEK_END); // set file pointer at end of file
   cnt=ftell(fp1); // count the size of file
  
   while(i<cnt) // create while loop until size of file
   {
       i++; // increment by 1 of i
       fseek(fp1,-i,SEEK_END); // set file pointer 0 to end
       fprintf(fp2,"%c",fgetc(fp1)); // write each character by character into file pointer fp2
   }
   // close all files
   close(fp1);
   close(fp2);
  
  
   return 0;
}

OUTPUT

D:\>reverse filein.txt fileOut

D:\>type fileOut
elif gnitset a si sihT

PROGRAM SCREENSHOTS***PLEASE DON'T FORGET TO GIVE THUMBS UP