C++友元函数

#include <iostream>
 
 

  #include <string>
 
 

  using namespace std;
 
 

  
 

  class Student
 
 

  {
 
 

  private:
 
 
 int age;
 
 

  public:
 
 
 setage(int n);
 
 
 friend int getage(Student &s);
   //
   定义友元函数
 
 

  };
 
 

  
 

  Student::setage(int n)
 
 

  {
 
 
 age=n;
 
 

  }
 
 

  int getage(Student &s)
 
 

  {
 
 
 return s.age;
   //友元函数可以有访问类私有变量的权限
 
 

  }
 
 

  
 

  int main()
 
 

  {
 
 
 Student jack;
 
 
 jack.setage(11);
 
 

  
 
 int result=getage(jack);
 
 
 cout<<result<<endl;
 
 

  
 
 return 0;
 
 

  }