I am having trouble with my switches.

[Louby85]

I am very new to java and I am trying to make a very simple calculator. I have written my code from scratch but I can't get my switch to work. It keeps only calculating case 3 no matter what I tell it to do. Could anyone help me to realise where I have gone wrong?

Here is my code

import java.util.Scanner;



public class Cal
{
public static void main(String[] args)
{
System.out.println("Enter first number");
Scanner sc = new Scanner(System.in);
double a = sc.nextDouble();

System.out.println("Enter second number");
Scanner dc = new Scanner(System.in);
double b = dc.nextDouble();

System.out.println("Enter + or - or /");
Scanner ss1 = new Scanner(System.in);
String s1 = ss1.next();

int switchy;

if(s1.equals("/"));
switchy=1;

if(s1.equals("-"));
switchy=2;

if(s1.equals("+"));
switchy=3;

switch (switchy) {

case 1: double h = a/b;
System.out.println(h);
break;

case 2: h = a-b;
System.out.println(h);
break;


case 3: h = a+b;
System.out.println(h);
break;



}
}
}

Thanks in advance.

[sehudson]

You forgot your brackets around your if statements. Also, don't forget to initialize switchy. You may want to catch the instance where someone enters something other than those symbols you want, or they enter a non number for your 1st two prompts. Try this:

       

public class Cal
{
public static void main(String[] args)
{ 
 System.out.println("Enter first number");
        Scanner sc = new Scanner(System.in);
        double a = sc.nextDouble();

        System.out.println("Enter second number");
        Scanner dc = new Scanner(System.in);
        double b = dc.nextDouble();

        System.out.println("Enter + or - or /");
        Scanner ss1 = new Scanner(System.in);
        String s1 = ss1.next();

        int switchy = 0;

        if (s1.equals("/")){
        switchy = 1;
        }
        if (s1.equals("-")){
        switchy = 2;
        }
        if (s1.equals("+")){
        switchy = 3;
        }

        switch (switchy) {

            case 1:
                double h = a / b;
                System.out.println(h);
                break;

            case 2:
                h = a - b;
                System.out.println(h);
                break;


            case 3:
                h = a + b;
                System.out.println(h);
                break;
        }

    }
}

[Louby85]

Thank you so much, I didn´t know I had to use brackets there. I now have a fully functioning basic calculator

[Junky]

Thank you so much, I didn´t know I had to use brackets there. I now have a fully functioning basic calculator

You don't have to use brackets. Your problem was you placed a semi-colon after the if statement, thus terminating it. So regardless of whether the if statements were true or not you always set switchy to 1 then 2 and finally 3.

By the way why are you using an if statement and a switch statement? Why not just move the code from your switch cases into the if statements?

[chinna]

Brackets is not mandatory. If your IF condition contains more 1 statements then you need to use brackets.
For and example

puclic String test(int value)
{
if (value = 0)
return 'Zero';
if (value <0)
{
value ++;
return 'more than zero'
}

}

[tnrh1]

You forgot your brackets around your if statements.

If you got just one statement you dont need brackets.

[Louby85]

Thanks so much. All this information has been very useful to me

[Norm]

If you always use brackets you rarely have the problem. Make it a habit to add the opening { and the closing } on the next line