Question

Write a program to calculate area of circle using friend function ?

Answer 1

#include <iostream>
#include <math.h>

using namespace std;
int area(double R)
{
double AREA2=0;
double Pi=3.14159265358979;
AREA2= Pi*R*R;
cout<<AREA2;
}

int main()
{

double r;
cout<<"enter R"<<endl;
cin>>r;
area(r);

return 0;
}