Contoh Coding Membuat Kalkulator Sederhana

package kalkulator;

public class Calculator extends javax.swing.JFrame {

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double num,ans;int calculation; public Calculator() {initComponents();jRadioButton1.setEnabled(false);} public void arithmetic_operation() {switch(calculation) {case 1 :ans= num + Double.parseDouble(jTextField1.getText());jTextField1.setText(Double.toString(ans));break; case 2 :ans= num - Double.parseDouble(jTextField1.getText());jTextField1.setText(Double.toString(ans));break; case 3 :ans= num * Double.parseDouble(jTextField1.getText());jTextField1.setText(Double.toString(ans));break; case 4 :ans= num / Double.parseDouble(jTextField1.getText());jTextField1.setText(Double.toString(ans));break;}} public void enable() {jTextField1.setEnabled(true);jRadioButton1.setEnabled(false);jRadioButton2.setEnabled(true);        jButton34.setEnabled(true);jButton36.setEnabled(true);jButton33.setEnabled(true);jButton30.setEnabled(true);jButton29.setEnabled(true);jButton31.setEnabled(true);jButton32.setEnabled(true);jButton26.setEnabled(true);jButton25.setEnabled(true);jButton27.setEnabled(true);jButton22.setEnabled(true);jButton21.setEnabled(true);jButton23.setEnabled(true);jButton24.setEnabled(true);jButton20.setEnabled(true);jButton16.setEnabled(true);jButton2.setEnabled(true);jButton28.setEnabled(true);} public void disable() {jTextField1.setEnabled(false);  jRadioButton1.setEnabled(true);jRadioButton2.setEnabled(false);jButton34.setEnabled(false);jButton36.setEnabled(false);jButton33.setEnabled(false);jButton30.setEnabled(false);jButton29.setEnabled(false);jButton31.setEnabled(false);jButton32.setEnabled(false);jButton26.setEnabled(false);jButton25.setEnabled(false);jButton27.setEnabled(false);jButton22.setEnabled(false);jButton21.setEnabled(false);jButton23.setEnabled(false);jButton24.setEnabled(false);jButton20.setEnabled(false);jButton16.setEnabled(false);jButton2.setEnabled(false);jButton28.setEnabled(false);} @SuppressWarnings("unchecked")Generated code private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {                                            // TODO add your handling code here:}                                            private void jRadioButton2ActionPerformed(java.awt.event.ActionEvent evt){                                              disable();}                                              private void jButton21ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "8");}                                          private void jButton25ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "5");}                                          private void jButton29ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() + "2");}                                          private void jButton33ActionPerformed(java.awt.event.ActionEvent evt) {                                          arithmetic_operation();jLabel1.setText("");}                                          private void jButton36ActionPerformed(java.awt.event.ActionEvent evt) {                    jTextField1.setText(jTextField1.getText() +  "."); }                                           private void jButton31ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "3"); }                                           private void jButton16ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(""); }                                           private void jButton28ActionPerformed(java.awt.event.ActionEvent evt) {                                          num = Double.parseDouble(jTextField1.getText()); calculation =3; jTextField1.setText(""); jLabel1.setText(num + "x"); }                                           private void jButton24ActionPerformed(java.awt.event.ActionEvent evt) {                                          num = Double.parseDouble(jTextField1.getText()); calculation =2; jTextField1.setText(""); jLabel1.setText(num + "-"); }                                           private void jButton30ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "1"); }                                           private void jButton26ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "4");        }                                           private void jButton27ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "6"); }                                           private void jButton22ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "7"); }                                           private void jButton23ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "9"); }                                           private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {                                          num = Double.parseDouble(jTextField1.getText()); calculation =1; jTextField1.setText(""); jLabel1.setText(num + "+"); }                                           private void jButton32ActionPerformed(java.awt.event.ActionEvent evt) {                                          num = Double.parseDouble(jTextField1.getText()); calculation =4; jTextField1.setText(""); jLabel1.setText(num + "/"); }                                           private void jButton34ActionPerformed(java.awt.event.ActionEvent evt) {                                          jTextField1.setText(jTextField1.getText() +  "0"); }                                           private void jRadioButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                              enable(); }                                               private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         int length= jTextField1.getText().length(); int number= jTextField1.getText().length() - 1; String store;   if(length > 0) { StringBuilder back= new StringBuilder(jTextField1.getText()); back.deleteCharAt(number); store=back.toString(); jTextField1.setText(store); } }                                          public static void main(String args[]) { /* Set the Nimbus look and feel */ Look and feel setting code (optional)   /* Create and display the form */ java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new Calculator().setVisible(true); } }); }   // Variables declaration - do not modify                     private javax.swing.ButtonGroup buttonGroup1; private javax.swing.JButton jButton16; private javax.swing.JButton jButton2; private javax.swing.JButton jButton20; private javax.swing.JButton jButton21; private javax.swing.JButton jButton22; private javax.swing.JButton jButton23; private javax.swing.JButton jButton24; private javax.swing.JButton jButton25; private javax.swing.JButton jButton26; private javax.swing.JButton jButton27; private javax.swing.JButton jButton28; private javax.swing.JButton jButton29; private javax.swing.JButton jButton30; private javax.swing.JButton jButton31; private javax.swing.JButton jButton32; private javax.swing.JButton jButton33; private javax.swing.JButton jButton34; private javax.swing.JButton jButton35; private javax.swing.JButton jButton36; private javax.swing.JLabel jLabel1; private javax.swing.JRadioButton jRadioButton1; private javax.swingg.JRadioButton jRadioButton2; private javax.swing.JTextField jTextField1; // End of variables declaration                   }