一个简单的c++函数调用

#include <iostream>
using namespace std;
int add(int num1,int num2)
{
	int sum = num1 + num2;
	return sum;
	
}
int main(){
	int a = 10;
	int b = 20;
	int sum=add(a, b);
	cout << "sum=" << sum << endl;
	a = 100;
	b = 500;
	sum = add(a, b);
	sum = add(a, b);
	cout << "sum=" << sum << endl;

	system("pause");
	return 0;

}