Menghitung keliling lingkaran (C++)

#include <cstdlib>
#include <iostream>

using namespace std;
class kll{
      public:
             int in();
             int proses();
      private:
              int l,p,k;
              };
int kll::in(){
    cout<<"Masukan panjang: ";
    cin>>p;
    cout<<"Masukan lebar: ";
    cin>>l;
}
int kll::proses(){
    k=2*(p+l);
    cout<<"Keliling ==> "<< k<<endl;
}
int main(int argc, char *argv[])
{
    kll x;
    x.in();
    x.proses();
    system("PAUSE");
    return EXIT_SUCCESS;
}