MEMBUAT LUAS LINGKARAN MENGGUNAKAN PROGRAM C++

#include<iostream>
using namespace std;
void lingkaran()
{
     system ("cls");
     float phi1;
     phi1 =3.14;
     cout<<"Insert the phi, please ! : ";
     cin>>phi1;
     int r;
     float luas;
     cout<<"Insert the r, please ! : ";
     cin>>r;
     cout<<"Insert the r, please ! : ";
     cin>>r;
     luas= phi1 * r * r;
     cout<<"The result is ="<<luas<<endl;
    
     }
     int main ()
     {
         char z;
     again:
           lingkaran () ;
           cout<<"Replay again ? (Y/N)"<<endl;
           cin>>z;
           if (z=='Y'||z=='Y')
           {
                              goto again;
                              }
}

SEMOGA BERMANFAAT ............. :)