[Help] Basic math program help. A easy to understand thread.

[MagicalPeppers]

Hi people, I am new to Java and I have been learning by way of books. Right now I am learning about loops. So to test my knowledge I decided to make a simple calculator. This calculator has no gui, as I don't know how to make them, but the code and logic should be easy to follow.

import java.util.Scanner;

public class main {
	public static void main(String[] args) {
		
		int a;
		int b;
		String calcType;
		
		// get input for var int a
		System.out.println("Enter your first number:");
		Scanner input1 = new Scanner(System.in);
		a = input1.nextInt();
		System.out.println("You entered " + a);
		
		//get the math operator to be use in the calculation - var string "calcType"
		System.out.println("Now choose your operator. (/*-+)");
		Scanner input2 = new Scanner(System.in);
		calcType = input2.next();
		System.out.println("You entered " + calcType);
		
		//get the input for var int b
		System.out.println("Now choose your last number.");
		Scanner input3 = new Scanner(System.in);
		b = input3.nextInt();
		System.out.println("You entered " + b);
		
		// Begin calculations!
		//This code figures out the math operator to be used and then does the appropriate calculation.
		if(calcType == "/") {
			double answer1 = a / b;
			System.out.println("The answer is: " + answer1);
		} else if(calcType == "*") {
			int answer2 = a * b;
			System.out.println("The answer is: " + answer2);
		} else if(calcType == "-") {
			int answer3 = a - b;
			System.out.println("The answer is: " + answer3);
		} else if(calcType == "+") {
			int answer4 = a + b;
			System.out.println("The answer is: " + answer4);
		} else {
			// Return if the calculation could not be completed.
			System.out.println("Houston we have a problem!");
		}

	}
}

Compiler Error: None
Works Correctly: No
Returns: Houston we have a problem!

I believe the problem is happening in the "Begin calculations section." I am trying to compare the string the user entered (eg /*-+) with a || operator to a typed out version of the entered operator.

This is probably very simple to all of you and I appreciate your time in reading my thread and helping me make this code work. Please tell me what is done wrong.

Thank you!

[JosAH]

Don't compare objects (such as Strings) for equality wth the == operator; use the .equals( ... ) method instead, e.g. s.equals("+").

kind regards,

Jos

[MagicalPeppers]

Don't compare objects (such as Strings) for equality wth the == operator; use the .equals( ... ) method instead, e.g. s.equals("+").

kind regards,

Jos

Thank you Jos for the quick response! I really appreciate you pointing out the correct syntax for me. And best of all I have learned something, which is awesome!

The new IF statement bock of code (works perfect):

// Begin calculations!
		//This code figures out the math operator to be used and then does the appropriate calculation.
		if(calcType.equals("/")) {
			double answer1 = a / b;
			System.out.println("The answer is: " + answer1);
		} else if(calcType.equals("*")) {
			int answer2 = a * b;
			System.out.println("The answer is: " + answer2);
		} else if(calcType.equals("-")) {
			int answer3 = a - b;
			System.out.println("The answer is: " + answer3);
		} else if(calcType.equals("+")) {
			int answer4 = a + b;
			System.out.println("The answer is: " + answer4);
		} else {
			// Return if the calculation could not be completed.
			System.out.println("Houston we have a problem!");
		}

Thanks again! you rock!