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Thread: I have tried making a simple random calculator and its not working?

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    Default I have tried making a simple random calculator and its not working?

    I have tried making this calculator to get used to working with classes, methods, return statements, etc..., but the method that should return my result won't return anything. I have tried using the debug mode in Eclipse but that didn't help me either.



    Main method:

    public class CalculatorMain { //class CalculatorMain
     
        public static void main(String[] args) { //main method
     
    	Calculator1 a = new Calculator1(); //new class a
     
    	JOptionPane.showMessageDialog(null, "This is a primitive Calculator"); //startup message
     
    	a.input(); //input method
     
    	double y = a.input(); //create y which equals the return value of input method
     
    	JOptionPane.showMessageDialog(null, y); //shows result
     
        }
     
    }

    Calculator method:

    package calculator;
     
    import javax.swing.JOptionPane;
     
    public class Calculator1 {
     
        double b;
        double a;
     
        double input()
        {
     
    	a = Double.parseDouble(JOptionPane.showInputDialog("Enter your first number: ")); //shows input and sets a
    	b = Double.parseDouble(JOptionPane.showInputDialog("Enter your first number: ")); //shows input and sets b
    	String c = JOptionPane.showInputDialog("Type a(dd), s(ubtract), m(ultiply), d(evide)"); //asks for a, b, c or d
     
    	if (c == "a"){
     
    	    return a + b;
     
    	}
    	else if (c == "s"){
     
    	    return a - b;
     
    	}
    	else if (c == "m"){
     
    	    return a * b;
     
    	}
    	else if (c == "d"){
     
    	    return a / b;
     
    	}
     
    	return 0;
     
        }
     
     
    }

    Thanks for any help, I am new to coding and teaching java to myself, so the only place I can go for help is the internet.

    -StackOfCookies


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    Default Re: I have tried making a simple random calculator and its not working?

    Please use [highlight=Java]//code goes here...[/highlight] tags when posting your code

  3. #3
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    Default Re: I have tried making a simple random calculator and its not working?

    From the Java String class descriptions of the 'equals()' method at Java String Class:

    equals

    public boolean equals(Object anObject)

    Compares this string to the specified object. The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.
    Bottom line: Don't use something like (c =="a") to compare one String to another. Use c.equals("a")


    Cheers!

    Z

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