Subtraction of two numbers using recursion Implemented by C++

#include<iostream.h>
int sub(int a, int b)
{
    int count = 0;
    if (a == b)
        return 0;

    if (a > b)
    {
        return ++count += sub (a-1, b);
    }
    else
        return --count += sub(a+1, b);
}


void main()
{
    int a,b,s;

    cout<<"Enter two numbers=";
    cin>>a>>b;
    s=sub(a,b);
    cout<<endl<<"subtraction of two numbers="<<s;
}