مثالهاي برنامه Cو c++

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
int main()
{
    FILE *in, *out ;
    char ch;
    clrscr();
    in = fopen("test.dat", "w");
    if (!in) {
       printf("cannot open file\n");
       getch();
       exit(1);
    }
    printf("\n enter characters($ for end):");
    do {
  ch = getchar();
  putc(ch, in);
    } while(ch != '$');
    fclose(in);
    out = fopen("output.dat", "w");
    if(!out) {
  printf("cannot open out file");
  getch();
  exit(1);
    }
    in = fopen("test.dat","r");
    if(!in) {
       printf("can not open input file");
       getch();
       exit(1);
    }
    ch = getc(in);
    while(ch != EOF) {
    putc(ch, out);
    ch = getc(in);
    }//end of while
    fclose(in);
    fclose(out);
    printf("\n file test.dat transfered to output.dat.");
    getch();
    return 0;
}