Question

(java)write a simple graphical calculator with four operations: addition,substractuon, multipication division, that must do the following:

a)it must support real and whole numbers (3.5 and 3 for instance)..

b)it must support negative numbers using a button "+/-" that allows changing between positivity and negativity of the number

c)the graphical interface of the calculator will include a matrix of buttons that include the digits 0,...,9 and "+" "-""*" "/" "." "+/-" and "=".

d)the calculator will include a text field that shows the input number or the result

e(each number represents one digit so it must have the ability to create a number that contains multiple digits(for instance 999 is 3 clicks on the number 9)

Answer 1

package hee;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
class CalC extends JFrame implements ActionListener {
static JFrame f;
  
static JTextField l;
  
String a0, a1, a2;
  
CalC()
{
a0 = a1 = a2 = "";
}
  
public static void main(String args[])
{
f = new JFrame("CALCULATOR");
  
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch (Exception e) {
System.err.println(e.getMessage());
}
  
CalC q= new CalC();

l = new JTextField(16);

l.setEditable(false);
  
JButton c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, ca, cs, cd, cm, ce, ceq, ceq1;
  
c0 = new JButton("0");
c1 = new JButton("1");
c2 = new JButton("2");
c3 = new JButton("3");
c4 = new JButton("4");
c5 = new JButton("5");
c6 = new JButton("6");
c7 = new JButton("7");
c8 = new JButton("8");
c9 = new JButton("9");   
ceq1 = new JButton("=");
  
ca = new JButton("+");
cs = new JButton("-");
cd = new JButton("/");
cm = new JButton("*");
ceq = new JButton("C");
  
ce = new JButton(".");
JPanel w = new JPanel();
  
cm.addActionListener(q);
cd.addActionListener(q);
cs.addActionListener(q);
ca.addActionListener(q);
c9.addActionListener(q);
c8.addActionListener(q);
c7.addActionListener(q);
c6.addActionListener(q);
c5.addActionListener(q);
c4.addActionListener(q);
c3.addActionListener(q);
c2.addActionListener(q);
c1.addActionListener(q);
c0.addActionListener(q);
ce.addActionListener(q);
ceq.addActionListener(q);
ceq1.addActionListener(q);
  
w.add(l);
w.add(ca);
w.add(c1);
w.add(c2);
w.add(c3);
w.add(cs);
w.add(c4);
w.add(c5);
w.add(c6);
w.add(cm);
w.add(c7);
w.add(c8);
w.add(c9);
w.add(cd);
w.add(ce);
w.add(c0);
w.add(ceq);
w.add(ceq1);
  

w.setBackground(Color.red);
  

f.add(w);
  
f.setSize(200, 200);
f.show();
}
public void actionPerformed(ActionEvent e)
{
String st = e.getActionCommand();
  
  
if ((st.charAt(0) >= '0' && st.charAt(0) <= '9') || st.charAt(0) == '.') {
  
if (!a1.equals(""))
a2 = a2 + st;
else
a0 = a0 + st;
  

l.setText(a0 + a1 + a2);
}
else if (st.charAt(0) == 'C') {
  
a0 = a1 = a2 = "";

l.setText(a0 + a1 + a2);
}
else if (st.charAt(0) == '=') {
  
double tee;
  
if (a1.equals("+"))
tee = (Double.parseDouble(a0) + Double.parseDouble(a2));
else if (a1.equals("-"))
tee = (Double.parseDouble(a0) - Double.parseDouble(a2));
else if (a1.equals("/"))
tee = (Double.parseDouble(a0) / Double.parseDouble(a2));
else
tee = (Double.parseDouble(a0) * Double.parseDouble(a2));
  
l.setText(a0 + a1 + a2 + "=" + tee);
  
a0 = Double.toString(tee);
a1 = a2 = "";
}
else {
if (a1.equals("") || a2.equals(""))
a1 = st;
else {
double tee;
  
if (a1.equals("+"))
tee = (Double.parseDouble(a0) + Double.parseDouble(a2));
else if (a1.equals("-"))
tee = (Double.parseDouble(a0) - Double.parseDouble(a2));
else if (a1.equals("/"))
tee = (Double.parseDouble(a0) / Double.parseDouble(a2));
else
tee = (Double.parseDouble(a0) * Double.parseDouble(a2));   
a0 = Double.toString(tee);
a1 = st;
a2 = "";
}
  
l.setText(a0 + a1 + a2);
}
}
}