#include<iostream>
using namespace std;
//值传递
//定义函数，实现两个数字进行交换函数
//如果函数不需要返回值，声明的时候可以写void

void swap(int num1 ,int num2)
{
    cout << "交换前：" << endl;
    cout << "num1 = " << num1 <<endl;
    cout << "num2 = " << num2 << endl;
    
    int temp = num1
    num1 = num2;
    num2 = temp;
    
    cout << "交换后：" << endl;
    cout << "num1 = " << num1 <<endl;
    cout << "num2 = " << num2 << endl;
    
    return;       //返回值不需要的时候，可以不写return
}
int main() {
    int a = 10；
    int b = 20；
    
     cout << "a = " << a << endl;
     cout << "b = " << b << endl;
        //函数的形参发生改变，并不会影响实参
    swap(a, b);    //相当于把a给了num 1  把b给了num2；
    
    system("pause");
    
    return 0;
}