A simple calculator using java

Use java to create a simple calculator-general Linux technology-Linux programming and kernel information. The following is a detailed description. There are two classes in total. It only completes the +,-, X, and merge operations.

The GUI only uses AWT, which is easy to understand.
Calculator. java

Public class Calculator {
Private String result = "0 ";
Private int op = 0, add = 1, sub = 2, mul = 3, div = 4;

Private double stringToDouble (String x ){
Double y = Double. parseDouble (x );
Return y;
}
Private void operate (String x ){
Double x1 = stringToDouble (x );
Double y = stringToDouble (result );
Switch (op ){
Case 0:
Result = x;
Break;
Case 1:
Result = String. valueOf (y + x1 );
Break;
Case 2:
Result = String. valueOf (y-x1 );
Break;
Case 3:
Result = String. valueOf (y * x1 );
Break;
Case 4:
If (x1! = 0 ){
Result = String. valueOf (y/x1 );
} Else {
Result = "The divisor can't be zero! ";
}
Break;
}
}

Public String opAdd (String x ){
Operate (x );
Op = add;
Return result;
}
Public String opSubtract (String x ){
Operate (x );
Op = sub;
Return result;
}
Public String opMultiply (String x ){
Operate (x );
Op = mul;
Return result;
}
Public String opDivide (String x ){
Operate (x );
Op = div;
Return result;
}
Public String opEquals (String x ){
Operate (x );
Op = 0;
Return result;
}
Public void opClean (){
Op = 0;
Result = "0 ";
}
}

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Second
CalculatorGUI. java

Import java. awt .*;
Import java. awt. event .*;
Import java. util. EventObject;

Public class CalculatorGUI {
Private Frame f;
Private Panel p1, p2;
Private Button b0, b1, b2, b3, b4, b5, b6, b7, b8, b9;
Private Button bPoint, bAdd, bDec, bMul, bDiv, bCal;
Private TextField tf;
Private String s, op;
Private Calculator cal = new Calculator ();
Private boolean ifOp;

Public CalculatorGUI (){
F = new Frame ("Calculator ");
P1 = new Panel ();
P2 = new Panel ();

B0 = new Button ("0 ");
B1 = new Button ("1 ");
B2 = new Button ("2 ");
B3 = new Button ("3 ");
B4 = new Button ("4 ");
B5 = new Button ("5 ");
B6 = new Button ("6 ");
B7 = new Button ("7 ");
B8 = new Button ("8 ");
B9 = new Button ("9 ");
BPoint = new Button (".");
BAdd = new Button ("+ ");
BDec = new Button ("-");
BMul = new Button ("*");
BDiv = new Button ("/");
BCal = new Button ("= ");

Tf = new TextField (25 );
Tf. setEditable (false );


}

Public void launchFrame (){
F. setSize (220,160 );
F. setResizable (false );
F. addWindowListener (new myWindowListener ());
P1.setLayout (new FlowLayout (FlowLayout. CENTER ));
P1.add (tf );
F. add (p1, BorderLayout. NORTH );
P2.setLayout (new GridLayout (4, 4 ));

B0.addActionListener (new setLabelText_ActionListener ());
B1.addActionListener (new setLabelText_ActionListener ());
B2.addActionListener (new setLabelText_ActionListener ());
B3.addActionListener (new setLabelText_ActionListener ());
B4.addActionListener (new setLabelText_ActionListener ());
B5.addActionListener (new setLabelText_ActionListener ());
B6.addActionListener (new setLabelText_ActionListener ());
B7.addActionListener (new setLabelText_ActionListener ());
B8.addActionListener (new setLabelText_ActionListener ());
B9.addActionListener (new setLabelText_ActionListener ());
BPoint. addActionListener (new setLabelText_ActionListener ());
BAdd. addActionListener (new setOperator_ActionListener ());
BDec. addActionListener (new setOperator_ActionListener ());
BMul. addActionListener (new setOperator_ActionListener ());
BDiv. addActionListener (new setOperator_ActionListener ());
BCal. addActionListener (new setOperator_ActionListener ());

P2.add (b7 );
P2.add (b8 );
P2.add (b9 );
P2.add (bAdd );
P2.add (b4 );
P2.add (b5 );
P2.add (b6 );
P2.add (bDec );
P2.add (b1 );
P2.add (b2 );
P2.add (b3 );
P2.add (bMul );
P2.add (b0 );
P2.add (bPoint );
P2.add (bCal );
P2.add (bDiv );
F. add (p2, BorderLayout. SOUTH );
F. setVisible (true );
}

Public void setTextFieldText_Temp (){
If (tf. getText (). length () <15 & (tf. getText (). indexOf (".") =-1 |! S. equals ("."))){
Tf. setText (tf. getText () + s );
} Else {
Tf. setText (tf. getText () + s). substring (0, 15 ));
}
}
Public void setTextFieldText (){
If (ifOp ){
IfOp = false;
Tf. setText ("");
SetTextFieldText_Temp ();
} Else {
SetTextFieldText_Temp ();
}
}

Public static void main (String [] args ){
CalculatorGUI calculator = new CalculatorGUI ();
Calculator. launchFrame ();
}

Class myWindowListener extends WindowAdapter {
Public void windowClosing (WindowEvent e ){
System. exit (0 );
}
}

Class setLabelText_ActionListener implements ActionListener {
Public void actionreceivmed (ActionEvent e ){
Button tempB = (Button) e. getSource ();
S = tempB. getLabel ();
SetTextFieldText ();
}
}

Class setOperator_ActionListener implements ActionListener {
Public void actionreceivmed (ActionEvent e ){
Button tempB = (Button) e. getSource ();
Op = tempB. getLabel ();
If (op. equals ("+ ")){
Tf. setText (cal. opAdd (tf. getText ()));
IfOp = true;
} Else if (op. equals ("-")){
Tf. setText (cal. opSubtract (tf. getText ()));
IfOp = true;
} Else if (op. equals ("*")){
Tf. setText (cal. opMultiply (tf. getText ()));
IfOp = true;
} Else if (op. equals ("/")){
Tf. setText (cal. opDivide (tf. getText ()));
IfOp = true;
} Else if (op. equals ("= ")){
Tf. setText (cal. opEquals (tf. getText ()));
IfOp = true;
}
}
}
}