Create a calculator with JCreator

Dear Java Friends;
I have got a problem when coding a java program to create a calculator with JCreator. Please help me to write codes for decimal point. :confused:

• Decimal point should not be set to the text more than 1 time until an operator is pressed.
• How can I use a Boolean value to solve this problem.

What code do you have so far?
You would use a boolean variable to remember an event. It would be false until the event happened, then it would be set true.

Code :

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import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Calculator extends JFrame{
 
	double firstNumber;
    boolean calculate = false;
    char operator;
 
	JTextField txtDisplay;
	JButton bt1;
	JButton bt2;
	JButton bt3;
	JButton bt4;
	JButton bt5;
	JButton bt6;
	JButton bt7;
	JButton bt8;
	JButton bt9;
	JButton bt0;
	JButton btAdd;
	JButton btSub;
	JButton btDiv;
	JButton btMul;
	JButton btEqual;
	JButton btDec;
	JButton btClear;
	JButton btSqrt;
 
	JPanel pane;
 
	Calculator(){
		setTitle("Calculator");
		txtDisplay=new JTextField();
		add(txtDisplay,"North");
 
		pane=new JPanel();
		pane.setLayout(new GridLayout(5,4,6,6));
		bt1=new JButton("1");
		bt1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("1");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "1");
		        }
            }
 
        } );
 
		bt2=new JButton("2");
		bt2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("2");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "2");
		        }
            }
 
        } );
		bt3=new JButton("3");
		bt3.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("3");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "3");
		        }
            }
 
        } );
		bt4=new JButton("4");
		bt4.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("4");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "4");
		        }
            }
 
        } );
		bt5=new JButton("5");
		bt5.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("5");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "5");
		        }
            }
 
        } );
		bt6=new JButton("6");		
		bt6.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("6");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "6");
		        }
            }
 
        } );
		bt7=new JButton("7");
		bt7.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("7");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "7");
		        }
            }
 
        } );
		bt8=new JButton("8");
		bt8.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("8");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "8");
		        }
            }
 
        } );
		bt9=new JButton("9");
		bt9.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("9");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "9");
		        }
            }
 
        } );
		bt0=new JButton("0");
		bt0.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        if (calculate) {
		            txtDisplay.setText("0");
		            calculate=false;
		        } else {
		            txtDisplay.setText(s + "0");
		        }
            }
 
        } );
        	btClear=new JButton("C");
		btClear.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {                   
		            txtDisplay.setText(" ");
 
            }
 
        } );
		btAdd=new JButton("+");
		btAdd.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
               	String s = txtDisplay.getText();
		        firstNumber = Double.parseDouble(s);
		        calculate = true;
		        operator='+';
 
    			}     
 
        });
		btSub=new JButton("-");
		btSub.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
               	String s = txtDisplay.getText();
		        firstNumber = Double.parseDouble(s);
		        calculate = true;
		        operator='-';
 
    			}     
 
        });
		btDiv=new JButton("/");
		btDiv.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
               	String s = txtDisplay.getText();
		        firstNumber = Double.parseDouble(s);
		        calculate = true;
		        operator='/';
 
    			}     
 
        });
		btMul=new JButton("*");
		btMul.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
               	String s = txtDisplay.getText();
		        firstNumber = Double.parseDouble(s);
		        calculate = true;
		        operator='*';
 
    			}     
 
        });
		btEqual=new JButton("=");
		btEqual.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
               	String s = txtDisplay.getText();
		        double secondNumber=Double.parseDouble(s);
		        double result=secondNumber;		         
		        switch(operator){
		            case '+':
		             result=firstNumber+secondNumber;
		             break;
		            case '-':
		             result=firstNumber-secondNumber;
		             break;
		            case '/':
		             result=firstNumber/secondNumber;
		             break;
		            case '*':
		             result=firstNumber*secondNumber;
		             break;		
		        }
 
			   	txtDisplay.setText(""+result);		 
    		}          
        });
		btDec=new JButton(".");
		btDec.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
            //    int count=0;
 
		        if (calculate) {
		            txtDisplay.setText(".");
		          	calculate=false;          		
 
		        } else {
		            txtDisplay.setText(s + ".");
		           // calculate=true;
		         }
 
 
            }
 
        } );
        btSqrt=new JButton("Sqrt");
		btSqrt.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
                String s = txtDisplay.getText();
		        s=txtDisplay.getText();	
             	double q=Math.sqrt(Double.parseDouble(s));
        	 	txtDisplay.setText(q+"");
 
		        }           	
        } );
 
		pane.add(bt1);
		pane.add(bt2);
		pane.add(bt3);
		pane.add(btAdd);
		pane.add(bt4);
		pane.add(bt5);
		pane.add(bt6);
		pane.add(btSub);
		pane.add(bt7);
		pane.add(bt8);
		pane.add(bt9);
		pane.add(btDiv);
		pane.add(bt0);
		pane.add(btDec);
		pane.add(btEqual);
		pane.add(btMul);
		pane.add(btClear);
		pane.add(btSqrt);
 
		add(pane);			
	}
 
}
class DemoFrame{
	public static void main(String args[]){
		Calculator c1=new Calculator();
		c1.pack();
		c1.show();
	}
}

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This is the code that I have coded. Please help me to re-correct my program, as the decimal point is not working properly.=((

Quote:

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the decimal point is not working properly

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Can your be more specific about the problem?
Show what program does, describe why that is wrong and show what it should do.

Hello Java Friends;
Sorry for the delay reply...
The Decimal Point is not working properly. :((
The program should not set the decimal point to a number more than one time; until an operator is pressed. I have given the code that I have coded. But I can't re-correct the error. Please help me to solve this problem. :(

Quote:

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program should not set the decimal point to a number more than one time

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It would help if you could post an example of the program doing this.
Use println() to output the wrong results with a comment about how its wrong.

It sounds like you need a flag to remember if a decimal point has been set and to not allow another if one has been entered.