C++ Program .Write a program to append the content of one file at the end of another file.

#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp;
char ch;
clrscr();
fp=fopen("b.txt","a");
if(fp==NULL)
  {
  printf("\n unable to open file");
  }
  while((ch=getchar())!=EOF)
  {
  fputc(ch,fp);
  }
  fclose(fp);
getch();
}