How to design a calculator which performs arithmetic operations using swings?

// Java program to create a simple calculator // with basic +, -, /, * using java swing elements import java.awt.event.*; import javax.swing.*; import java.awt.*; class calculator extends JFrame implements ActionListener { // create a frame static JFrame f; // create a textfield static JTextField l; // store oprerator and operands String s0, s1, s2; // default constrcutor calculator() { s0 = s1 = s2 = ""; } // main function public static void main(String args[]) { // create a frame f = new JFrame("calculator"); try { // set look and feel UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (Exception e) { System.err.println(e.getMessage()); } // create a object of class calculator c = new calculator(); // create a textfield l = new JTextField(16); // set the textfield to non editable l.setEditable(false); // create number buttons and some operators JButton b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bs, bd, bm, be, beq, beq1; // create number buttons b0 = new JButton("0"); b1 = new JButton("1"); b2 = new JButton("2"); b3 = new JButton("3"); b4 = new JButton("4"); b5 = new JButton("5"); b6 = new JButton("6"); b7 = new JButton("7"); b8 = new JButton("8"); b9 = new JButton("9"); // equals button beq1 = new JButton("="); // create operator buttons ba = new JButton("+"); bs = new JButton("-"); bd = new JButton("/"); bm = new JButton("*"); beq = new JButton("C"); // create . button be = new JButton("."); // create a panel JPanel p = new JPanel(); // add action listeners bm.addActionListener(c); bd.addActionListener(c); bs.addActionListener(c); ba.addActionListener(c); b9.addActionListener(c); b8.addActionListener(c); b7.addActionListener(c); b6.addActionListener(c); b5.addActionListener(c); b4.addActionListener(c); b3.addActionListener(c); b2.addActionListener(c); b1.addActionListener(c); b0.addActionListener(c); be.addActionListener(c); beq.addActionListener(c); beq1.addActionListener(c); // add elements to panel p.add(l); p.add(ba); p.add(b1); p.add(b2); p.add(b3); p.add(bs); p.add(b4); p.add(b5); p.add(b6); p.add(bm); p.add(b7); p.add(b8); p.add(b9); p.add(bd); p.add(be); p.add(b0); p.add(beq); p.add(beq1); // set Background of panel p.setBackground(Color.blue); // add panel to frame f.add(p); f.setSize(200, 220); f.show(); } public void actionPerformed(ActionEvent e) { String s = e.getActionCommand(); // if the value is a number if ((s.charAt(0) >= '0' && s.charAt(0) <= '9') || s.charAt(0) == '.') { // if operand is present then add to second no if (!s1.equals("")) s2 = s2 + s; else s0 = s0 + s; // set the value of text l.setText(s0 + s1 + s2); } else if (s.charAt(0) == 'C') { // clear the one letter s0 = s1 = s2 = ""; // set the value of text l.setText(s0 + s1 + s2); } else if (s.charAt(0) == '=') { double te; // store the value in 1st if (s1.equals("+")) te = (Double.parseDouble(s0) + Double.parseDouble(s2)); else if (s1.equals("-")) te = (Double.parseDouble(s0) - Double.parseDouble(s2)); else if (s1.equals("/")) te = (Double.parseDouble(s0) / Double.parseDouble(s2)); else te = (Double.parseDouble(s0) * Double.parseDouble(s2)); // set the value of text l.setText(s0 + s1 + s2 + "=" + te); // convert it to string s0 = Double.toString(te); s1 = s2 = ""; } else { // if there was no operand if (s1.equals("") || s2.equals("")) s1 = s; // else evaluate else { double te; // store the value in 1st if (s1.equals("+")) te = (Double.parseDouble(s0) + Double.parseDouble(s2)); else if (s1.equals("-")) te = (Double.parseDouble(s0) - Double.parseDouble(s2)); else if (s1.equals("/")) te = (Double.parseDouble(s0) / Double.parseDouble(s2)); else te = (Double.parseDouble(s0) * Double.parseDouble(s2)); // convert it to string s0 = Double.toString(te); // place the operator s1 = s; // make the operand blank s2 = ""; } // set the value of text l.setText(s0 + s1 + s2); } } } read less

import javax.swing.*; import java.awt.event.*; class Calc implements ActionListener { JFramef; JTextFieldt; JButton b1,b2,b3,b4,b5,b6,b7,b8,b9,b0,bdiv,bmul,bsub,badd,bdec,beq,bdel,bclr; staticdoublea=0,b=0,result=0; staticintoperator=0; Calc() { f=newJFrame("Calculator"); t=newJTextField(); b1=newJButton("1"); b2=newJButton("2"); b3=newJButton("3"); b4=newJButton("4"); b5=newJButton("5"); b6=newJButton("6"); b7=newJButton("7"); b8=newJButton("8"); b9=newJButton("9"); b0=newJButton("0"); bdiv=newJButton("/"); bmul=newJButton("*"); bsub=newJButton("-"); badd=newJButton("+"); bdec=newJButton("."); beq=newJButton("="); bdel=newJButton("Delete"); bclr=newJButton("Clear"); t.setBounds(30,40,280,30); b7.setBounds(40,100,50,40); b8.setBounds(110,100,50,40); b9.setBounds(180,100,50,40); bdiv.setBounds(250,100,50,40); b4.setBounds(40,170,50,40); b5.setBounds(110,170,50,40); b6.setBounds(180,170,50,40); bmul.setBounds(250,170,50,40); b1.setBounds(40,240,50,40); b2.setBounds(110,240,50,40); b3.setBounds(180,240,50,40); bsub.setBounds(250,240,50,40); bdec.setBounds(40,310,50,40); b0.setBounds(110,310,50,40); beq.setBounds(180,310,50,40); badd.setBounds(250,310,50,40); bdel.setBounds(60,380,100,40); bclr.setBounds(180,380,100,40); f.add(t); f.add(b7); f.add(b8); f.add(b9); f.add(bdiv); f.add(b4); f.add(b5); f.add(b6); f.add(bmul); f.add(b1); f.add(b2); f.add(b3); f.add(bsub); f.add(bdec); f.add(b0); f.add(beq); f.add(badd); f.add(bdel); f.add(bclr); f.setLayout(null); f.setVisible(true); f.setSize(350,500); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setResizable(false); b1.addActionListener(this); b2.addActionListener(this); b3.addActionListener(this); b4.addActionListener(this); b5.addActionListener(this); b6.addActionListener(this); b7.addActionListener(this); b8.addActionListener(this); b9.addActionListener(this); b0.addActionListener(this); badd.addActionListener(this); bdiv.addActionListener(this); bmul.addActionListener(this); bsub.addActionListener(this); bdec.addActionListener(this); beq.addActionListener(this); bdel.addActionListener(this); bclr.addActionListener(this); } publicvoidactionPerformed(ActionEvente) { if(e.getSource()==b1) t.setText(t.getText().concat("1")); if(e.getSource()==b2) t.setText(t.getText().concat("2")); if(e.getSource()==b3) t.setText(t.getText().concat("3")); if(e.getSource()==b4) t.setText(t.getText().concat("4")); if(e.getSource()==b5) t.setText(t.getText().concat("5")); if(e.getSource()==b6) t.setText(t.getText().concat("6")); if(e.getSource()==b7) t.setText(t.getText().concat("7")); if(e.getSource()==b8) t.setText(t.getText().concat("8")); if(e.getSource()==b9) t.setText(t.getText().concat("9")); if(e.getSource()==b0) t.setText(t.getText().concat("0")); if(e.getSource()==bdec) t.setText(t.getText().concat(".")); if(e.getSource()==badd) { a=Double.parseDouble(t.getText()); operator=1; t.setText(""); } if(e.getSource()==bsub) { a=Double.parseDouble(t.getText()); operator=2; t.setText(""); } if(e.getSource()==bmul) { a=Double.parseDouble(t.getText()); operator=3; t.setText(""); } if(e.getSource()==bdiv) { a=Double.parseDouble(t.getText()); operator=4; t.setText(""); } if(e.getSource()==beq) { b=Double.parseDouble(t.getText()); switch(operator) { case1:result=a+b; break; case2:result=a-b; break; case3:result=a*b; break; case4:result=a/b; break; default:result=0; } t.setText(""+result); } if(e.getSource()==bclr) t.setText(""); if(e.getSource()==bdel) { Strings=t.getText(); t.setText(""); for(inti=0;i<s.length()-1;i++) t.setText(t.getText()+s.charAt(i)); } } publicstaticvoidmain(String...s) { newCalc(); } } read less