program menampilkan deret bilangan fibonaci dg interatif for, while,do while

#include <cstdlib>
#include <iostream>

using namespace std;
class fibonaci{
      friend istream& operator >> (istream&, fibonaci&);
      friend ostream& operator << (ostream&, fibonaci&);

      public :
             void iteratif();
             void iteratif2();
      private:
              int a,b,c,batas;
      };
     
      istream& operator >>(istream& in, fibonaci& masuk){
               cout<<"Dengan menggunakan Iteratif while " <<endl;
               cout<<"Masukkan batas nilai   :"; in>>masuk.batas;
               cout<<"Bilangan Fibonacci < " << masuk.batas <<" adalah\no,1";
               }
     
      ostream& operator << (ostream& out, fibonaci& keluar){
           keluar.a=0;keluar.b=1;
           while(true){
                       keluar.c=keluar.a+keluar.b;
                       if(keluar.c>keluar.batas) break;
                       cout<<"," <<keluar.c;
                       keluar.a=keluar.b;
                       keluar.b=keluar.c;
                       }
                       }
                      
      void fibonaci::iteratif(){
           a=0;b=1;
            cout<<"Bilangan Fibonacci < " <<batas <<" adalah\no,1";
           do{
                      c=a+b;
                       if(c>batas) break;
                       cout<<"," <<c;
                       a=b;
                       b=c;
                       }
           while(true);
           }
          
      void fibonaci::iteratif2(){
           a=0;b=1;
            cout<<"Bilangan Fibonacci < " <<batas <<" adalah\no,1";
           for(c=1;c<batas;c++){
           c=a+b;
           cout<<"," <<c;
           a=b;
           b=c;
           }
           }
     
int main(int argc, char *argv[])
{
    fibonaci x;
   
    cout<<"Menampilkan deret bilangan fibonacci iterative ";   
    cout<<endl;
    cin>>x;
    cout<<x;
    cout<<endl;
    cout<<endl;
   
    cout<<"Dengan do while " <<endl;
    x.iteratif();
    cout<<endl;
    cout<<endl;
   
    cout<<"Dengan For " <<endl;
    x.iteratif2();
    cout<<endl;
 
    system("PAUSE");
    return EXIT_SUCCESS;
}