C File Copy

#include <stdio.h>
#include <stdlib.h>
//  w w  w. ja  v a 2s .c om
int main(int argc, char *argv[])
{
  FILE *in, *out;
  char ch;

  if(argc!=3) {
    printf("You forgot to enter a filename.\n");
    exit(1);
  }

  if((in=fopen(argv[1], "rb")) == NULL) {
    printf("Cannot open input file.\n");
    exit(1);
  }
  if((out=fopen(argv[2], "wb")) == NULL) {
    printf("Cannot open output file.\n");
    exit(1);
  }

  while(!feof(in)) {
    ch = getc(in);
    if(ferror(in)) {
      printf("Read Error");
      clearerr(in);
      break;
    } else {
      if(!feof(in)) putc(ch, out);
      if(ferror(out)) {
        printf("Write Error");
        clearerr(out);
        break;
      }
    }
  }
  fclose(in);
  fclose(out);

  return 0;
}