Program kalkulator sederhana C++

#include <iostream>
#include <cstdlib>
#include <iomanip>
#include <string>
#include <math.h>
using namespace std;
class KALKULATOR{
  friend ostream & operator << ( ostream &, const KALKULATOR & );
  friend istream & operator >> ( istream &, KALKULATOR & );

public:
  void MENU();
  void ulang();
  void tambah();
  void kurang();
  void kali();
  void bagi();
  void INPUT1();
  void INPUT2();
  void pilihan1();
  void pilihan2();
  void pilihan3();
  void sines();
  void cosines();
  void tangen();
  void logku();
  void log10ku();
  void sqrtku();
  void expku();
 
private:
  char  opt;     
  int pilih;
  float hasil0;
  float hasil1;
  float a;
  float b;
  float c;
 
};

 void KALKULATOR::MENU(){
  cout << endl;
  cout << " |===================================|" << endl;
  cout << " |       KALKULATOR SEDERHANA                     |" << endl;
  cout << " |===================================|" << endl;
  cout << " |===================================|" << endl;
  cout << " |  http://samsulfti.blogspot.com/                                 |" << endl;
  cout << " |===================================|" << endl;
  cout << endl;
  cout << " |==================================================================|" << endl;
  cout << " [ B ] Menu Pilihan1 kalkulator Biasa                                               ]" << endl;
  cout << " [ F ] Menu Untuk Kalkulator fungsi Matematika[sin][cos][tgen][dll] ]" << endl;
  cout << " [ ext ] Keluar program                                                                                                 ]" << endl;
  cout << " |==================================================================|" << endl;

  cout << " Pilih Kalkulator Yang Akan Di Gunakan :";
  cin >> opt;

  if ( opt == 'B' ){
    pilihan1();
  }
  else if ( opt == 'F' ){
    pilihan2();
  }
 
  else if ( opt == 'ext' ){
    exit(0);
  }
}

 void KALKULATOR::pilihan1(){
 
  cout << "Operator Yang Akan Di Gunakan" << endl;
  cout << "1. Tambah (+)" << endl;
  cout << "2. Kurang (-)" << endl;
  cout << "3. Kali   (*)" << endl;
  cout << "4. Bagi   (/)" << endl;

  cout << "Pilih Operator yang akan di gunakan : ";
  cin >> opt;

  if ( opt == '+' ){
    tambah();
  }
  else if ( opt == '-' ){
    kurang();
  }
  else if ( opt == '*' ){
    kali();
  }
  else if ( opt == '/' ){
    bagi();
  }
  else {
    cout << " Maaf Operator Yang Anda Masukan Tidak Tersedia ";
  }
}

 void KALKULATOR::pilihan2(){

  cout << "Operator fungsi matematika" << endl;
  cout << "1. Sin      [ S  ] " << endl;
  cout << "2. Cos      [ C  ]" << endl;
  cout << "3. Tan      [ T  ]" << endl;
  cout << "4. log      [ L  ]" << endl;
  cout << "5. log10    [ L10]" << endl;
  cout << "6. sqrt     [ Sq ]" << endl;
  cout << "7. exp      [ Ep ]" << endl;

  cout << "Pilih Operator yang akan di gunakan : ";
  cin >>opt;

  if ( opt == 'S' ){
    sines();
  }
  else if ( opt == 'C' ){
    cosines();
  }
  else if ( opt == 'Tg' ){
    tangen();
  }
  else if ( opt == 'L' ){
    logku();
  }
  else if ( opt == 'L10' ){
    log10ku();
  }
  else if ( opt == 'Sq' ){
    sqrtku();
  }
  else if ( opt == 'Ep' ){
    expku();
  }
  else {
    cout << " Maaf Operator Yang Anda Masukan Tidak Tersedia ";
  }

}
   void KALKULATOR::INPUT1(){
   cout << "Masukkan bilangan pertama:";
   cin >> a;
   cout << "Masukkan bilangan kedua:";
   cin >> b;
}

   void KALKULATOR::tambah(){
   INPUT1();

   hasil0 = a + b;
   cout <<"Hasilnya Adalah:"<< hasil0<<endl;
}

   void KALKULATOR::kurang(){
   INPUT1();

   hasil0 = a - b;
   cout <<"Hasilnya Adalah:"<< hasil0<<endl;
}

   void  KALKULATOR::kali(){
  INPUT1();
   hasil0 = a * b;
   cout <<"Hasilnya Adalah:"<< hasil0<<endl;
}

   void  KALKULATOR::bagi(){
   INPUT1();
   hasil0 = a / b;
   cout <<"Hasilnya Adalah:"<< hasil0<<endl;
}

   void KALKULATOR::INPUT2(){
   cout << "Masukkan bilangan:";
   cin >> c;

}

   void KALKULATOR::sines(){
   INPUT2();
   hasil1 = sin( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}
   void KALKULATOR::cosines(){
   INPUT2();
   hasil1 = cos( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}
   void KALKULATOR::tangen(){
   INPUT2();
   hasil1 = tan( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}
   void KALKULATOR::logku(){
   INPUT2();
   hasil1 = log( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}

   void KALKULATOR::log10ku(){
   INPUT2();
   hasil1 = log10( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}

   void KALKULATOR::sqrtku(){
   INPUT2();
   hasil1 = sqrt( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}
   void KALKULATOR::expku(){
   INPUT2();
   hasil1 = exp( c );
   cout <<"Hasilnya Adalah:"<< hasil1<<endl;
}          
  main(){
  KALKULATOR pheewe;
  pheewe.MENU();
 
  system("PAUSE");
  return EXIT_SUCCESS;
}

Program tahun kabisat ( jeliot )

import jeliot.io.*;

public class tahun_kabisat{
int x;
public int bil(int x){
return x;
}
            public final void kabisat()
            {
            int bil;
             bil=Input.readInt();
               if(bil % 4 == 0)
              {
                               System.out.print("Tahun kabisat.\n");
                  }
              else
              {
                  System.out.print("Tahun bukan kabisat.\n");
              }
          
              System.out.print(bil);
          
           }
            public tahun_kabisat()
            {
            System.out.print("Program untuk menampilkan tahun kabisat");
            System.out.print("\n");
                                  }
}
public class MyClass {
    public static void main() {
   tahun_kabisat x = new tahun_kabisat();
        x.kabisat();
System.out.print("\n");
    }
}