Add the new ‘include’ commands at the beginning of the file around the same place of other ‘include’ commands that already exists.
OLD
#include <stdlib.h>
#include <fstream>
#include <iostream>
#include "vadd.h"
NEW
#include <stdlib.h>
#include <fstream>
#include <iostream>
#include "vadd.h"
#include "ap_int.h"
#include <stdio.h>