#include <iostream.h>
int add(int &a, int &b)
{
	int iRet = 0;
	iRet = a + b;
	a = 100; //改變形參的值
	return iRet;
}
void main()
{
	int num1 = 10, num2 = 20;
	cout << add(num1 , num2) << endl;
	cout << "num1 = " <<num1 <<endl;
}