I have written this code of calculator.
However, at runtime, if I use the minus button, it becomes plus.
I had tried to delete the code of that plus/minus button but the problem still there.
I have already tried everything, the only useful thing that I found is that the “-” string did not register.
Code:
public class Calculator extends javax.swing.JFrame {
static String OP = "",
operations = "[+|-|x|/|0|-|.]",
anw = "noInputYet";
static float result,
firstNumber = 0,
secondNumber = 0;
static double prNumber = 0 ;
static int numberClick = 0;
private void bt1ActionPerformed(java.awt.event.ActionEvent evt) {
// Button 1
if (calScreen.getText().matches(operations)) {
calScreen.setText("1");}
else if (result != 0) {
calScreen.setText("1");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "1");
}
}
private void bt2ActionPerformed(java.awt.event.ActionEvent evt) {
// button 2
if (calScreen.getText().matches(operations)) {
calScreen.setText("2");}
else if (result != 0) {
calScreen.setText("2");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "2");
}
}
private void bt3ActionPerformed(java.awt.event.ActionEvent evt) {
// button 3
if (calScreen.getText().matches(operations)) {
calScreen.setText("3");}
else if (result != 0) {
calScreen.setText("3");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "3");
}
}
private void bt9ActionPerformed(java.awt.event.ActionEvent evt) {
// button 9
if (calScreen.getText().matches(operations)) {
calScreen.setText("9");}
else if (result != 0) {
calScreen.setText("9");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "9");
}
}
private void bt8ActionPerformed(java.awt.event.ActionEvent evt) {
// button 8
if (calScreen.getText().matches(operations)) {
calScreen.setText("8");}
else if (result != 0) {
calScreen.setText("8");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "8");
}
}
private void bt7ActionPerformed(java.awt.event.ActionEvent evt) {
// button 7
if (calScreen.getText().matches(operations)) {
calScreen.setText("7");}
else if (result != 0) {
calScreen.setText("7");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "7");
}
}
private void bt4ActionPerformed(java.awt.event.ActionEvent evt) {
// button 4
if (calScreen.getText().matches(operations)) {
calScreen.setText("4");}
else if (result != 0) {
calScreen.setText("4");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "4");
}
}
private void bt5ActionPerformed(java.awt.event.ActionEvent evt) {
// button 5
if (calScreen.getText().matches(operations)) {
calScreen.setText("5");}
else if (result != 0) {
calScreen.setText("5");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "5");
}
}
private void bt6ActionPerformed(java.awt.event.ActionEvent evt) {
// button 6
if (calScreen.getText().matches(operations)) {
calScreen.setText("6");}
else if (result != 0) {
calScreen.setText("6");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "6");
}
}
private void btDotActionPerformed(java.awt.event.ActionEvent evt) {
// button dot
if (calScreen.getText().matches(operations)) {
calScreen.setText("0.");}
else if (result != 0) {
calScreen.setText("0.");
result = 0;}
else {
calScreen.setText(calScreen.getText() + ".");
}
}
private void bt0ActionPerformed(java.awt.event.ActionEvent evt) {
// button 0
if (calScreen.getText().matches(operations)) {
calScreen.setText("0");}
else if (result != 0) {
calScreen.setText("0");
result = 0;}
else {
calScreen.setText(calScreen.getText() + "0");
}
}
private void btEqualActionPerformed(java.awt.event.ActionEvent evt) {
// Result
secondNumber = Float.parseFloat(calScreen.getText());
switch(OP){
case "+" :{
result = firstNumber + secondNumber;break;
}
case "-":{
result = firstNumber - secondNumber;break;
}
case "*":{
result = firstNumber * secondNumber;break;
}
case "/":{
result = firstNumber / secondNumber;break;
}
default :{
result = 0 ;break;
}
}
if (result == (int)result){
calScreen.setText(Integer.toString((int)result));
anw = Integer.toString((int)result);
}//If result is integer
else {calScreen.setText(Float.toString(result));
anw = Float.toString(result);
}// If result is flaot
firstNumber= 0;
secondNumber = 0;
numberClick = 0;
}
private void btPlusActionPerformed(java.awt.event.ActionEvent evt) {
//Plus button
firstNumber = Float.parseFloat(calScreen.getText());
OP = "+";
numberClick += 1;
if (!calScreen.getText().equals("+") && numberClick == 2){
btEqual.doClick();
}
else {
calScreen.setText("+");
}
}
private void btMinusActionPerformed(java.awt.event.ActionEvent evt) {
// minus button
firstNumber = Float.parseFloat(calScreen.getText());
OP = "-";
numberClick += 1;
if (!calScreen.getText().equals("-") && numberClick == 2){
btEqual.doClick();
}
else {
calScreen.setText("-");
}
}
private void btMultiActionPerformed(java.awt.event.ActionEvent evt) {
// Multiply
firstNumber = Float.parseFloat(calScreen.getText());
OP = "*";
numberClick += 1;
if (!calScreen.getText().equals("x") && numberClick == 2){
btEqual.doClick();
}
else {
calScreen.setText("x");
}
}
private void btDivideActionPerformed(java.awt.event.ActionEvent evt) {
// divide button
firstNumber = Float.parseFloat(calScreen.getText());
OP = "/";
numberClick += 1;
if (!calScreen.getText().equals("/") && numberClick == 2){
btEqual.doClick();
}
else {
calScreen.setText("/");
}
}
private void btAnsActionPerformed(java.awt.event.ActionEvent evt) {
// Answer button
if (!anw.equals("noInputYet")){
calScreen.setText(anw);
}
}
private void btSignActionPerformed(java.awt.event.ActionEvent evt) {
// button Change sign
}
private void btPiActionPerformed(java.awt.event.ActionEvent evt) {
// precent button
prNumber = Double.parseDouble(calScreen.getText())/100;
if (prNumber == (int)prNumber){
calScreen.setText(Integer.toString((int)prNumber));
anw = Integer.toString((int)prNumber);
result = (int)prNumber;
}//prNumber is integer
else {calScreen.setText(Double.toString(prNumber));
anw = Double.toString(prNumber);
result = Float.parseFloat(Double.toString(prNumber));
}// If prNumber is flaot
}
private void ButtonAllClearActionPerformed(java.awt.event.ActionEvent evt) {
// ALL clear button
calScreen.setText("0");
firstNumber = 0;
secondNumber = 0;
result = 0;
numberClick = 0;
anw = "noInputYet";
}
private void btPwOf2ActionPerformed(java.awt.event.ActionEvent evt) {
// button power of 2
result = Float.parseFloat(calScreen.getText()) * Float.parseFloat(calScreen.getText());
if (result == (int)result){
calScreen.setText(Integer.toString((int)result));
anw = Integer.toString((int)result);
}//prNumber is integer
else {calScreen.setText(Float.toString(result));
anw = Float.toString(result);
}// If prNumber is flaot
}
private void calScreenActionPerformed(java.awt.event.ActionEvent evt) {
// Screen of Calculator
}
Answer
Take a look at your btMinusActionPerformed method:
private void btMinusActionPerformed(java.awt.event.ActionEvent evt) {
// minus button
firstNumber = Float.parseFloat(calScreen.getText());
OP = "-";
numberClick += 1;
if (!calScreen.getText().equals("-") && numberClick == 2){
btEqual.doClick();
}
else {
calScreen.setText("-"); // <- What does this do?
}
}
Then take a look at the btEqualActionPerformed method:
private void btEqualActionPerformed(java.awt.event.ActionEvent evt) {
// Result
// What is getText() going to return if you pressed the minus button?
secondNumber = Float.parseFloat(calScreen.getText());
{ ... } // Omitted for brevity
}
Follow that through logically and you’ll notice that when you click the buttons for 1, -, and 2, you will read in 1 and -2. You’re already storing the operand in OP, so what you’ll do is 1 - (-2), which does actually equal 3. Your problem is in btMinusActionPerformed – that’s where you need to fix your code.
Additionally, your operations regular expression isn’t quite correctly defined. You haven’t escaped either the - or the ., so they aren’t going to work in the way that you expect them to.
operations = "[+|\-|x|/|0|\.]", // ^ ^ // Note the escape characters at these two locations
That should make your regex work in the way you intended for it to work.
An alternative solution would be to remove:
calScreen.setText("-");
From your btMinusActionPerformed method (and the corresponding lines from the other three operator’s methods), which would mean that the regex wasn’t necessary.