import javax.swing.JButton; 

/* 

* To change this template, choose Tools | Templates 

* and open the template in the editor. 

*/ 

/** 

* 

* @author arief pham pham 

*/ 

public class kalkulator extends javax.swing.JFrame { 

String angka; 

Double jumlah, bilangansatu, bilangandua; 

int option; 

/** 

* Creates new form kalkulator 

*/ 

public kalkulator() { 

initComponents(); 

angka=""; 

private void layarActionPerformed(java.awt.event.ActionEvent evt) { 

// TODO add your handling code here: 

layar.setText(""); 

} 

private void tombolNolActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="0"; 

layar.setText(angka); 

} 

private void tombolSatuActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="1"; 

layar.setText(angka); 

private void tombolDuaActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="2"; 

layar.setText(angka); 

} 

private void tombolTigaActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="3"; 

layar.setText(angka); 

} 

private void tombolEmpatActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="4"; 

layar.setText(angka); 

} 

private void tombolLimaActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="5"; 

layar.setText(angka); 

} 

private void tombolEnamActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="6"; 

layar.setText(angka); 

} 

private void tombolTujuhActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="7"; 

layar.setText(angka); 

} 

private void tombolDelapanActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="8"; 

layar.setText(angka); 

} 

private void tombolSembilanActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="9"; 

layar.setText(angka); 

} 

private void tombolBagiActionPerformed(java.awt.event.ActionEvent evt) { 

bilangansatu = Double.parseDouble(angka); 

layar.setText("/"); 

angka =""; 

option =1; 

} 

private void tombolKaliActionPerformed(java.awt.event.ActionEvent evt) { 

bilangansatu = Double.parseDouble(angka); 

layar.setText("*"); 

angka =""; 

option =4; 

} 

private void tombolKurangActionPerformed(java.awt.event.ActionEvent evt) { 

bilangansatu = Double.parseDouble(angka); 

layar.setText("-"); 

angka =""; 

option =3; 

} 

private void tombolTambahActionPerformed(java.awt.event.ActionEvent evt) { 

bilangansatu = Double.parseDouble(angka); 

layar.setText("+"); 

angka =""; 

option =2; 

} 

private void tombolTitikActionPerformed(java.awt.event.ActionEvent evt) { 

angka +="."; 

layar.setText(angka); 

} 

private void tombolCActionPerformed(java.awt.event.ActionEvent evt) { 

angka =""; 

layar.setText("0"); 

} 

private void tombolSamadenganActionPerformed(java.awt.event.ActionEvent evt) { 

switch(option){ 

case 1: 

bilangandua = Double.parseDouble(angka); 

jumlah = bilangansatu / bilangandua; 

angka = Double.toString(jumlah); 

layar.setText(angka); 

break; 

case 2: 

bilangandua = Double.parseDouble(angka); 

jumlah = bilangansatu + bilangandua; 

angka = Double.toString(jumlah); 

layar.setText(angka); 

break; 

case 3: 

bilangandua = Double.parseDouble(angka); 

jumlah= bilangansatu - bilangandua; 

angka = Double.toString(jumlah); 

layar.setText(angka); 

break; 

case 4: 

bilangandua = Double.parseDouble(angka); 

jumlah = bilangansatu * bilangandua; 

angka = Double.toString(jumlah); 

layar.setText(angka); 

break; 

default: 

break; 

} 

} 

private void tombolKeluarActionPerformed(java.awt.event.ActionEvent evt) { 

// TODO add your handling code here: 

System.exit(0); 

} 

public static void main(String args[]) { 

/* Set the Nimbus look and feel */ 

//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) "> 

/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel. 

* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 

*/ 

try { 

for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) { 

if ("Nimbus".equals(info.getName())) { 

javax.swing.UIManager.setLookAndFeel(info.getClassName()); 

break; 

} 

} 

} catch (ClassNotFoundException ex) { 

java.util.logging.Logger.getLogger(kalkulator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 

} catch (InstantiationException ex) { 

java.util.logging.Logger.getLogger(kalkulator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 

} catch (IllegalAccessException ex) { 

java.util.logging.Logger.getLogger(kalkulator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 

} catch (javax.swing.UnsupportedLookAndFeelException ex) { 

java.util.logging.Logger.getLogger(kalkulator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 

} 

//</editor-fold> 

/* Create and display the form */ 

java.awt.EventQueue.invokeLater(new Runnable() { 

public void run() { 

new kalkulator().setVisible(true); 

} 

}); 

} 

// Variables declaration - do not modify 

private javax.swing.JLabel jLabel1; 

private javax.swing.JTextField layar; 

private javax.swing.JButton tombolBagi; 

private javax.swing.JButton tombolC; 

private javax.swing.JButton tombolDelapan; 

private javax.swing.JButton tombolDua; 

private javax.swing.JButton tombolEmpat; 

private javax.swing.JButton tombolEnam; 

private javax.swing.JButton tombolKali; 

private javax.swing.JButton tombolKeluar; 

private javax.swing.JButton tombolKurang; 

private javax.swing.JButton tombolLima; 

private javax.swing.JButton tombolNol; 

private javax.swing.JButton tombolSamadengan; 

private javax.swing.JButton tombolSatu; 

private javax.swing.JButton tombolSembilan; 

private javax.swing.JButton tombolTambah; 

private javax.swing.JButton tombolTiga; 

private javax.swing.JButton tombolTitik; 

private javax.swing.JButton tombolTujuh; 

// End of variables declaration } 

Read more: http://probase-tama.blogspot.com/2013/02/membuat-program-kalkulator-sederhana_3791.html#ixzz2oLUvHSJS