交換兩個整數的方法比較

#include <iostream>

using namespace std;

void swap0(int x,int y)//形參的交換，沒有變化

{
int temp;
temp = x;
x = y;
y = temp;
}

void swap1(int *x,int *y)//指針傳遞（地址傳遞）形參是兩個整型指針，調用的時候傳入整型的地址，
{
int temp;
temp = *x;
*x = *y;
*y = temp;
}

void swap2(int &x,int &y)//引用傳遞，形參是兩個整型的引用，調用swap時，x，y初始化爲main函數中的x，y的別名，簡單高效！
{
int temp;
temp = x;
x = y;
y = temp;
}

void main()
{
int x = 10, y = 20;


cout<<"swap0 before:x = "<<x<<"  y = "<<y<<endl;
swap0(x,y);//傳值
cout<<"swap0  after:x = "<<x<<"  y = "<<y<<endl;
 
cout<<"swap1 before:x = "<<x<<"  y = "<<y<<endl;
swap1(&x,&y);//傳地址（傳指針）
cout<<"swap1  after:x = "<<x<<"  y = "<<y<<endl;
 
cout<<"swap2 before:x = "<<x<<"  y = "<<y<<endl;
swap2(x,y);//（引用）
cout<<"swap2  after:x = "<<x<<"  y = "<<y<<endl;
system("pause");

}

運行結果：

swap0 before:x = 10  y = 20
swap0  after:x = 10  y = 20
swap1 before:x = 10  y = 20
swap1  after:x = 20  y = 10
swap2 before:x = 20  y = 10
swap2  after:x = 10  y = 20