Thread: 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

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