#include <stdio.h>
int main()
{
  FILE *fp, *fp2;
  char c, open[100], output[100];
  int codekey=0;
  printf("enter openfile...\n");
  scanf("%s", open);
  if ((fp = fopen(open,"r")) == NULL){
    printf("%s//File not found!\n", open);
    exit(1);
  }
  printf("enter output file name...\n");
  scanf("%s", output);
  printf("enter CODE KEY...\n");
  scanf("%d", &codekey);
  printf("please wait...\n");
  fp2 = fopen(output, "w");
  printf("OPEN --%s--...\n", output);
  while ((c=getc(fp)) != EOF){
    putc(c-codekey, fp2);
  }
  printf("DECODING FINISHED!\n");
  fclose(fp);
  printf("CLOSE --%s--...\n", open);
  fclose(fp2);
  printf("CLOSE --%s--...\n", output);
  printf("COMPLETED!\n");
}