Create an applet that will do simple addition and subtraction for numbers. You m
ID: 3559858 • Letter: C
Question
Create an applet that will do simple addition and subtraction for numbers. You must create the calculator exactly as shown below to get the credits. That is, exact number of buttons and the exact layout of the buttons.
I must turn in all .java files and .html files
Secondly, add the ActionListener and the actionPerformed so that by pressing the button, the display shows the key pressed.
c) Then, do the simple addition and subtraction for 1 digit numbers
What the sample output must look like:
Thanks!
Explanation / Answer
import java.awt.*;
import java.awt.event.*;
public class calculator extends java.applet.Applet implements ActionListener {
TextField txtTotal = new TextField("");
Button button[] = new Button[10];
Button divide = new Button("/");
Button mult = new Button("*");
Button plus = new Button ("+");
Button minus = new Button("-");
Button isequalto = new Button("=");
Button clear = new Button("CA");
double num ,numtemp ;
int counter;
String strnum = "",strnumtemp = "" ;
String op = "";
public void operation() {
counter ++;
if (counter == 1) {
numtemp = num;
strnum = "";
num = 0;
}else{
if (op == "+") numtemp += num;
else if (op == "-") numtemp -= num;
else if (op == "*") numtemp = numtemp * num;
else if (op == "/") numtemp = numtemp / num;
strnumtemp = Double.toString(numtemp);
txtTotal.setText(strnumtemp);
strnum = "";
num = 0;
}
}
public void init() {
setLayout(null);
plus.setBackground(Color.blue);
plus.setForeground(Color.white);
minus.setBackground(Color.blue);
minus.setForeground(Color.white);
divide.setBackground(Color.blue);
divide.setForeground(Color.white);
isequalto.setBackground(Color.blue);
isequalto.setForeground(Color.white);
mult.setBackground(Color.blue);
mult.setForeground(Color.white);
clear.setBackground(Color.blue);
clear.setForeground(Color.red);
for(int i = 0;i <= 9; i ++) {
button[i] = new Button(String.valueOf(i));
button[i].setBackground(Color.orange);
button[i].setForeground(Color.blue);
}
button[1].setBounds(0,53,67,53);
button[2].setBounds(67,53,67,53);
button[3].setBounds(134,53,67,53);
button[4].setBounds(0,106,67,53);
button[5].setBounds(67,106,67,53);
button[6].setBounds(134,106,67,53);
button[7].setBounds(0,159,67,53);
button[8].setBounds(67,159,67,53);
button[9].setBounds(134,159,67,53);
for (int i = 1;i <= 9; i ++) {
add(button[i]);
}
txtTotal.setBounds(0,0,200,53);
add(txtTotal);
plus.setBounds(0,212,67,53);
add(plus);
button[0].setBounds(67,212,67,53);
add(button[0]);
minus.setBounds(134,212,67,53);
add(minus);
divide.setBounds(134,264,67,53);
add(divide);
isequalto.setBounds(67,264,67,53);
add(isequalto);
mult.setBounds(0,264,67,53);
add(mult);
add(clear);
}
public void start() {
for(int i = 0;i <= 9; i ++) {
button[i].addActionListener(this);
}
plus.addActionListener(this);
minus.addActionListener(this);
divide.addActionListener(this);
mult.addActionListener(this);
isequalto.addActionListener(this);
clear.addActionListener(this);
}
public void stop() {
for(int i = 0;i <= 9; i ++) {
button[i].addActionListener(null);
}
plus.addActionListener(null);
minus.addActionListener(null);
divide.addActionListener(null);
mult.addActionListener(null);
isequalto.addActionListener(null);
clear.addActionListener(null);
}
public void actionPerformed(ActionEvent e) {
for(int i = 0;i <= 9; i++) {
if (e.getSource() == button[i]) {
play(getCodeBase(),i + ".au");
strnum += Integer.toString(i);
txtTotal.setText(strnum);
num = Double.valueOf(strnum).doubleValue();
}
}
if (e.getSource() == plus) {
operation();
op = "+";
}
if (e.getSource() == minus) {
operation();
op = "-";
}
if (e.getSource() == divide) {
operation();
op = "/";
}
if (e.getSource() == mult) {
operation();
op = "*";
}
if (e.getSource() == isequalto) {
if (op == "+") numtemp += num;
else if (op == "-") numtemp -= num;
else if (op == "*") numtemp = numtemp * num;
else if (op == "/") numtemp = numtemp / num;
strnumtemp = Double.toString(numtemp);
txtTotal.setText(strnumtemp);
strnumtemp = "";
numtemp = 0;
strnum = "";
num = 0;
counter = 0;
}
if (e.getSource() == clear) {
txtTotal.setText("0");
strnumtemp = "";
numtemp = 0;
strnum = "";
num = 0;
counter = 0;
}
}
}
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