C++ examples for Class:friend
Add friend function to access private members
#include <iostream> #include <cmath> using namespace std; // declaration section class Complex/*from w w w . ja va 2 s .c om*/ { // friends list friend double addReal(const Complex&, const Complex&); friend double addImag(const Complex&, const Complex&); private: double realPart; double imaginaryPart; public: Complex(double real = 0.0, double imag = 0.0) // inline constructor { realPart = real; imaginaryPart = imag; } void showComplexValues(); }; // implementation section void Complex::showComplexValues() { char sign = '+'; if (imaginaryPart < 0) sign = '-'; cout << realPart << ' ' << sign << ' ' << abs(imaginaryPart) << 'i'; } // friend implementations double addReal(const Complex& a, const Complex& b) { return(a.realPart + b.realPart); } double addImag(const Complex& a, const Complex& b) { return(a.imaginaryPart + b.imaginaryPart); } int main() { Complex a(3.2, 5.6), b(1.1, -8.4); double re, im; cout << "The first complex number is "; a.showComplexValues(); cout << "\nThe second complex number is "; b.showComplexValues(); re = addReal(a,b); im = addImag(a,b); Complex c(re,im); // create a new Complex object cout << "\n\nThe sum of these two complex numbers is "; c.showComplexValues(); return 0; }