引用必须初始化
初始化后不可以更改了
#include<iostream>
using namespace std;
int main()
{
int a = 10;
//int &b;
int &b = a;//int &b ；//错误的 必须初始化
int c = 20;
b = c;//赋值操作，而不是更改引用
cout << "a= " << a << endl;
cout << "b= " << b << endl;
cout << "c= " << c << endl;
system("pause");
return 0;
}
