// C++ program to demonstrate example of// friend function with class#include <iostream>usingnamespacestd;classNumber{private:inta;public:voidgetNum(intx);//declaration of friend functionfriendvoidprintNum(Number NUM); };//class member function definitionsvoidNumber::getNum(intx...
$ g++ -c A.cpp In file included from A.cpp:1:0: A.h: In function ‘std::ostream&operator<<(std::ostream&,constusr::A&)’: A.h:10:17: error: ‘intusr::A::m_x’ isprivateintm_x; ^ A.cpp:7:13: error: withinthiscontext os << a.m_x; ^ ...
Consider the following program −Live Demo #include <iostream> using namespace std; class Box { double width; public: friend void printWidth( Box box ); void setWidth( double wid ); }; // Member function definition void Box::setWidth( double wid ) { width = wid; } // Note: ...
// classes_as_friends1.cpp// compile with: /cclassB;classA{public:intFunc1( B& b );private:intFunc2( B& b ); };classB{private:int_b;// A::Func1 is a friend function to class B// so A::Func1 has access to all members of BfriendintA::Func1( B& ); };intA::Func1(...
width << endl; } // Main function for the program int main() { Box box; // set box width without member function box.setWidth(10.0); // Use friend function to print the wdith. printWidth( box ); return 0; } 复制尝试一下 Width of box : 10 复制...
What is Friend Function in C++?Friend functions in C++ allow external functions or classes to access private and protected members of a class. This can be useful for sharing data between different parts of a program, but it is important to use friend functions carefully to maintain the ...
1. The friend function can access private and protected data members. 2. Friend function cannot call with the help of Object of that class, it is call by using normal ‘C’ function. 3. Generally, friend function can take Object as a argument. ...
I have this program with a friend function defined inside the class, that compiles with gcc and clang but is rejected by msvc. #include<iostream>template<typenameT>classOuter{structInner;friendvoidfoo(); };template<typenameT>structOuter<T>::Inner ...
void someFunction( const TestClass< T > *someTestClass ) { } U:\test>g++ -c testClass.cpp In file included from testClass.cpp:1: testClass.h:10: warning: friend declaration `void someFunction(const TestClass<T> *)' testClass.h:10: warning: declares a non-template function testClass...
如何在C ++代码中使用朋友函数? In a C++ program, using a friend function requires a few steps. First, the friend keyword must be used to designate the function as a friend of the class. Then, the function must be defined outside of the class, but have access to all of the private me...