#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
void mySwap(int a, int b)
{
int tmp = a;
a = b;
b = tmp;
cout << "mySwap::a = " << a << endl;
cout << "mySwap::b = " << b << endl;
}
void test01()
{
int a = 10;
int b = 20;
mySwap(a, b); //值传递
cout << "a = " << a << endl;
cout << "b = " << b << endl;
}
//地址传递
void mySwap2(int * a, int * b)
{
int tmp = *a;
*a = *b;
*b = tmp;
}
void test02()
{
int a = 10;
int b = 20;
mySwap2(&a, &b);
cout << "a = " << a << endl;
cout << "b = " << b << endl;
}
//引用传递 类似传地址
void mySwap3(int &a, int &b) //&a = a &b = b
{
int tmp = a;
a = b;
b = tmp;
}
void test03()
{
int a = 10;
int b = 20;
mySwap3(a, b);
cout << "a = " << a << endl;
cout << "b = " << b << endl;
}
//引用的注意事项
//1、 引用必须引一块合法的内存空间
//2、不要返回局部变量的引用
int& doWork()
{
int a = 10;
return a;
}
void test04()
{
//int &a = 10; // 引用必须引一块合法的内存空间
int &ret = doWork();
cout << "ret = " << ret << endl; //第一次10是编译器做了优化
cout << "ret = " << ret << endl;
cout << "ret = " << ret << endl;
cout << "ret = " << ret << endl;
cout << "ret = " << ret << endl;
}
int& doWork2()
{
static int a = 10;
return a;
}
void test05()
{
int &ret = doWork2();
//如果函数的返回值是引用，那么这个函数调用可以作为左值
doWork2() = 1000; //相当于写了 a = 1000;
}
int main(){
//test01();
//test02();
//test03();
//test04();
test05();
system("pause");
return EXIT_SUCCESS;
}
