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1. C / ANSI-C
2. File
3. File Compare

Compare files

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
  FILE *fp1, *fp2;
  char ch1, ch2, same;
  unsigned long l;

  if(argc!=3) {
    printf("Usage: compare <file 1> <file 2>\n");
    exit(1);
  }

  /* open first file */
  if((fp1 = fopen(argv[1], "rb"))==NULL) {
    printf("Cannot open first file.\n");
    exit(1);
  }

  /* open second file */
  if((fp2 = fopen(argv [2], "rb"))==NULL) {
    printf("Cannot open second file.\n");
    exit(1);
  }

  l = 0;
  same = 1;
  /* compare the files */
  while(!feof(fp1)) {
    ch1 = fgetc(fp1);
    if(ferror(fp1)) {
      printf("Error reading first file.\n");
      exit(1);
    }
    ch2 = fgetc(fp2);
    if(ferror(fp2)) {
      printf("Error reading second file.\n");
      exit(1);
    }
    if(ch1 != ch2) {
      printf("Files differ at byte number %lu", l);
      same = 0;
      break;
    }
    l++;
  }
  if(same) 
      printf("Files are the same.\n");

  if(fclose( fp1 ) == EOF) {
    printf("Error closing first file.\n");
    exit(1);
  }

  if(fclose( fp2 ) == EOF) {
    printf("Error closing second file.\n");
    exit(1);
  }

  return 0;
}

           
       

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