If we declare a function int disp(T4Tutorials_Strong_Numbers); as a friend function friend int disp(T4Tutorials_Strong_Numbers); in a class class T4Tutorials_Strong_Numbers , then this function int disp(T4Tutorials_Strong_Numbers); can access the private and protected members of the class T4Tutorials_Strong_Numbers. You must know that a global function can also be declared as a friend function of the class.
Syntax of friend function in C++
class class_name_T4Tutorials_Strong_Numbers { … friend return_type function_name(arguments); … }
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#include<iostream> using namespace std; class T4Tutorials_Strong_Numbers { protected : int i, n, n1; int s1 , j, k; int en, sn; long T4Tutorials_factorial; public : input() { s1 = 0; T4Tutorials_factorial = 0; cout<<"Please input the starting range of number : "<<endl; cin>>sn; cout<<"Please input the ending range of number : "<<endl; cin>>en; } friend int disp(T4Tutorials_Strong_Numbers); }; int disp(T4Tutorials_Strong_Numbers a) { cout<<"The Strong numbers are: "<<endl; for (a.k = a.sn; a.k <= a.en; a.k++) { a.n1=a.k; a.s1 = 0; for (a.j = a.k; a.j > 0; a.j = a.j / 10) { a.T4Tutorials_factorial = 1; for (a.i = 1; a.i <= a.j % 10; a.i++) { a.T4Tutorials_factorial = a.T4Tutorials_factorial * a.i; } a.s1 = a.s1 + a.T4Tutorials_factorial; } if (a.s1 == a.n1) { cout << a.n1 << " "; } } cout<<endl; } int main() { T4Tutorials_Strong_Numbers a; a.input(); disp(a); } |