目录

引用变量

1.1 创建引用变量

引用变量的程序示例

程序运行结果

引用变量

引用是对已定义的变量的别名，比如一个人的大名和小名，这指的都是一个人。区别指针与引用变量

1.1 创建引用变量

比如要将rodents作为rats变量的别名，可以这样做：

int rats;

int & rodents =rats;

 注意，&这里不是地址运算符，而是类型标识符一部分，int & 指的是指向int 的引用

引用变量的程序示例

  

   

    

     

    
    

     

      //firstref.cpp -- defining and using a reference
     
    
   

    

     

    
    

     

      //引用
     
    
   

    

     

    
    

     

      #include<iostream>
     
    
   

    

     

    
    

     

      int main()
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     
	using namespace std;
     
    
   

    

     

    
    

     
	int rats = 101;
     
    
   

    

     

    
    

     
	int & rodents = rats;//rodents这里是rats的引用
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "原始的" << endl;
     
    
   

    

     

    
    

     
	cout << "rats = " << rats;
     
    
   

    

     

    
    

     
	cout << ", rodents = " << rodents << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "rodents++后的" << endl;
     
    
   

    

     

    
    

     

      	rodents++;
     
    
   

    

     

    
    

     
	cout << "rats = " << rats;
     
    
   

    

     

    
    

     
	cout << ", rodents = " << rodents << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "显示其地址" << endl;
     
    
   

    

     

    
    

     
	cout << "rats address = " << &rats;
     
    
   

    

     

    
    

     
	cout << ", rodents address = " << &rodents << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	return 0;
     
    
   

    

     

    
    

     

      }
     
    
  
 

程序运行结果

必须在声明引用变量时进行初始化，这点和指针不一样

如果非要拉上关系，引用更接近const指针，必须在创建时进行初始化，一旦关联，就一直效忠。

int & rodents =rats;

实际上是下述代码的伪装

int * const pr = &rats;

试图将变量的引用改变的程序示例

  

   

    

     

    
    

     

      // secref.cpp -- defining and using a reference
     
    
   

    

     

    
    

     

      #include<iostream>
     
    
   

    

     

    
    

     

      int main()
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     
	using namespace std;
     
    
   

    

     

    
    

     
	int rats = 101;
     
    
   

    

     

    
    

     
	int & rodents = rats; //引用
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "原始的" << endl;
     
    
   

    

     

    
    

     
	cout << "rats = " << rats;
     
    
   

    

     

    
    

     
	cout << ", rodents = " << rodents << endl << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "显示其原始地址" << endl;
     
    
   

    

     

    
    

     
	cout << "rats address = " << &rats;
     
    
   

    

     

    
    

     
	cout << ", rodents address = " << &rodents << endl << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	int bunnies = 50;
     
    
   

    

     

    
    

     

      	rodents = bunnies;//这里可以改变引用吗？
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "观测是否发生了改变" << endl;
     
    
   

    

     

    
    

     
	cout << "bunnies = " << bunnies;
     
    
   

    

     

    
    

     
	cout << ", rats = " << rats;
     
    
   

    

     

    
    

     
	cout << ", rodents = " << rodents << endl << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	cout << "--------------------" << endl;
     
    
   

    

     

    
    

     
	cout << "显示其现在的地址" << endl;
     
    
   

    

     

    
    

     
	cout << "bunnies address = " << &bunnies;
     
    
   

    

     

    
    

     
	cout << ", rodents address = " << &rodents << endl << endl;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
	return 0;
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      }
     
    
  
 

咋一看，改变成功了，但是发现bunnies地址与rats和rodents的地址并不同，这是因为上述语句等效于：

rats = bunnies；

也就意味着可以通过初始化声明来设置引用，但不能通过赋值来设置。

文章来源: kings.blog.csdn.net，作者：人工智能博士，版权归原作者所有，如需转载，请联系作者。

原文链接：kings.blog.csdn.net/article/details/90436997