Software Engineering Second Job

The code runs as follows:

Mport javax.swing.*;
Import java.awt.*;
Import java.awt.event.*;

public class Heya1 extends JFrame implements ActionListener
{
Private Boolean dotexist, operated, equaled; Boolean variable for help operation
Private double storednumber; The current results
Private char lastoperator; Represents the previous operator
Private JTextField operation; Result Bar
Private JButton dot, plus, minus, multi, div, sqrt, equal, CHANGEPN, clear; Operator
Private jbutton[] numbers; Digital

Construction person
Public Heya1 ()
{
Settitle ("Calculator");
Initialize variables
Dotexist = false; Indicates whether the current number has a decimal point
operated = FALSE; Indicates whether any operator is pressed
equaled = false; Indicates whether the equals sign is pressed
Storednumber = 0;
Lastoperator = '? ';
Initializing window variables
Operation = new JTextField ("0");
Operation.seteditable (FALSE);
Numbers = new JBUTTON[10];
for (int i = 0; i <; i++)
Numbers[i] = new JButton ("" + i);
dot = new JButton (".");
plus = new JButton ("+");
minus = new JButton ("-");
Multi = new JButton ("*");
div = new JButton ("/");
sqrt = new JButton ("√");
equal = new JButton ("=");
CHANGEPN = new JButton ("±");
Clear = new JButton ("AC");
Put the Window object into the window
GridBagLayout layout = new GridBagLayout ();
Getcontentpane (). setlayout (layout);
AddComponent (layout, operation, 0, 0, 4, 1);
AddComponent (layout, numbers[1], 1, 0, 1, 1);
AddComponent (layout, numbers[2], 1, 1, 1, 1);
AddComponent (layout, numbers[3], 1, 2, 1, 1);
AddComponent (layout, numbers[4], 2, 0, 1, 1);
AddComponent (layout, numbers[5], 2, 1, 1, 1);
AddComponent (layout, numbers[6], 2, 2, 1, 1);
AddComponent (layout, numbers[7], 3, 0, 1, 1);
AddComponent (layout, numbers[8], 3, 1, 1, 1);
AddComponent (layout, numbers[9], 3, 2, 1, 1);
AddComponent (Layout, dot, 4, 0, 1, 1);
AddComponent (layout, numbers[0], 4, 1, 1, 1);
AddComponent (Layout, sqrt, 4, 2, 1, 1);
AddComponent (layout, plus, 1, 3, 1, 1);
AddComponent (layout, minus, 2, 3, 1, 1);
AddComponent (layout, multi, 3, 3, 1, 1);
AddComponent (Layout, Div, 4, 3, 1, 1);
AddComponent (Layout, equal, 5, 0, 2, 1);
AddComponent (Layout, CHANGEPN, 5, 2, 1, 1);
AddComponent (Layout, clear, 5, 3, 1, 1);
}

How to react to a button
public void actionperformed (ActionEvent e)
{
JButton btn = (JButton) e.getsource ();
if (btn = = clear)
{
Operation.settext ("0");
Dotexist = false;
Storednumber = 0;
Lastoperator = '? ';
}
else if (btn = = equal)
{
Operate (' = ');
equaled = true;
}
else if (btn = = Plus)
{
Operate (' + ');
equaled = false;
}
else if (btn = = minus)
{
Operate ('-');
equaled = false;
}
else if (btn = = multi)
{
Operate (' * ');
equaled = false;
}
else if (btn = = div)
{
Operate ('/');
equaled = false;
}
else if (btn = = CHANGEPN)
{
Operate (' P ');
Operate (' = ');
equaled = true;
}
else if (btn = = sqrt)
{
Operate (' s ');
Operate (' = ');
equaled = true;
}
Else
{
if (equaled)
Storednumber = 0;
for (int i = 0; i <; i++)
if (btn = = Numbers[i])
{
if (Operation.gettext (). Equals ("0"))
Operation.settext ("" + i);
else if (! Operated)
Operation.settext (Operation.gettext () + i);
Else
{
Operation.settext ("" + i);
operated = FALSE;
}
}
if (btn = = Dot &&! dotexist)
{
Operation.settext (Operation.gettext () + ".");
Dotexist = true;
}
}
}
How to perform the operation
private void Operate (char operator)
{
Double currentnumber = double.valueof (Operation.gettext ()). Doublevalue ();
if (Lastoperator = = '? ')
Storednumber = Currentnumber;
else if (Lastoperator = = ' + ')
Storednumber + = Currentnumber;
else if (lastoperator = = '-')
Storednumber-= Currentnumber;
else if (lastoperator = = ' * ')
Storednumber *= Currentnumber;
else if (lastoperator = = '/')
Storednumber/= Currentnumber;
else if (lastoperator = = ' P ')
Storednumber *=-1;
else if (Lastoperator = = ' s ')
Storednumber = Math.sqrt (Currentnumber);
else if (lastoperator = = ' = ' && equaled)
Storednumber = Currentnumber;
Operation.settext ("" + storednumber);
operated = TRUE;
Lastoperator = operator;
}

A quick way to use GridBagLayout
private void AddComponent (GridBagLayout layout, Component Component, int row, int col, int width, int height)
{
gridbagconstraints constraints = new gridbagconstraints ();
Constraints.fill = Gridbagconstraints.both;
Constraints.insets = new Insets (10, 2, 10, 2);
CONSTRAINTS.WEIGHTX = 100;
constraints.weighty = 100;
Constraints.gridx = col;
Constraints.gridy = row;
Constraints.gridwidth = width;
Constraints.gridheight = height;
Layout.setconstraints (component, constraints);
If (component instanceof JButton)
((JButton) component). addActionListener (this);
Getcontentpane (). Add (component);
}

The Main method initializes and displays the window
public static void Main (string[] args)
{
HEYA1 calc = new Heya1 ();
Calc.setsize (290, 400);
Calc.setvisible (TRUE);
}
}

The addition runs as follows:

The code for 1:4+5 is as follows

Subtraction runs as follows

2:5-4 of the running results

:

3: Multiplication Run

Results of 4*5 operation

4: Division of the Run

Results of 5/4

Software Engineering Second Job