C++ : 引用的实质理解 !!!!

   引用的定义:在类型和标识符之间加上一个取地址符,说明该标识符为指定类型的引用

        如: int &ref = num;   就是ref是一个int型的引用

 

  引用有什么作用呢?  看下面代码就知道了:

   #include <iostream> using namespace std; int main() { int num = 12; int num1 = 21; int &ref = num; cout<<"ref = "<<ref<<",num = "<<num<<endl; num = 16; cout<<"ref = "<<ref<<",num = "<<num<<endl; ref = 18; cout<<"ref = "<<ref<<",num = "<<num<<endl; cout<<"&ref = "<<&ref<<",&num = "<<&num<<endl; ref = num1; /*不是ref成为num1的引用,而是将num1的值传递给ref */ cout<<"ref = "<<ref<<",num1 = "<<num1<<endl; cout<<"&ref = "<<&ref<<",&num = "<<&num<<",&num1 = "<<&num1<<endl; return 0; }

 

第一行输出 :   ref = 12,num = 12

第二行输出 :   ref = 16,