If and Switch same task, different results?

Question

I have a switch and an if statement, and they are equivalent. They should both take a string, if yes do something, and if no do another thing. The if statement does nothing regardless of what is entered, but the switch statement does. Why is that?

Here is the if statement:

if (yes.equals("yes")){
    System.out.println ("Enter your first number");
    fnum = x.nextDouble();
    System.out.println ("Enter your second number");
    snum = x.nextDouble();
    calculations(fnum, snum);
}
if (yes.equals("No")) {
    System.out.println("okay, bye then!");
}

Here is the switch:

switch (yesno){
    case "yes":  
        System.out.println ("Enter your first number");
        fnum = x.nextDouble();
        System.out.println ("Enter your second number");
        snum = x.nextDouble();
        calculations(fnum, snum);
        break;
    case "no":
        System.out.println("k bye");

This is not a duplicate, because the issue is in the if statement. I have been marked duplicate for my switch.

1) Your switch needs a `break` statement. 2) your "creative" use of code indentation needs improvement. — Hovercraft Full Of Eels, Aug 14 '15 at 23:47
You are right about the break statement (which I added on edit), but why isn't the if statement working? — Ruchir Baronia, Aug 14 '15 at 23:50
Again: **PLEASE** fix your indentation. It's terrible. Do this, unless your goal is really to try to confuse folks who are trying to understand your code. — Hovercraft Full Of Eels, Aug 14 '15 at 23:52
Edit: I have tried to fix the indentation for you, but in the future, please do this yourself, as you do yourself no favor posting unreadable code. Also, if you're having problems with the `if` block, then you may need to show more code and go into more detail as to how or why it's not working. You're probably better off using `equalsIgnoreCase` and not `equals` by the way. — Hovercraft Full Of Eels, Aug 14 '15 at 23:56
@rakeb.void: your "duplicate" question is not correct as that addresses switch cases before Java 1.6 when Strings were not allowed in the case statements. That has since been fixed/improved. — Hovercraft Full Of Eels, Aug 15 '15 at 00:00
.... and made it worse by adding unnecessary white space. Editing back. Please leave it be. — Hovercraft Full Of Eels, Aug 15 '15 at 00:01
Do you know what the issue may be in the if statement; this is properly formatted code. — Ruchir Baronia, Aug 15 '15 at 00:02
Regarding your `if` block, in its present state, your question of "what is wrong with this block of code" is unanswerable. Please see my comment above for how to address this. — Hovercraft Full Of Eels, Aug 15 '15 at 00:11
Your switch statement, which is working, uses the variable `yesno`. Your if statement is not using that variable, but instead a variable called `yes'. Is that the only problem? — Carl Manaster, Aug 15 '15 at 00:21
Thank you Carl, you're right! I thought that yes and yesno would be equal, but they weren't...? Any idea why? — Ruchir Baronia, Aug 15 '15 at 00:25
No idea whatsoever. Look at your code and see where the variables are being set. — Carl Manaster, Aug 15 '15 at 00:29
In other words -- any idea why the code I'm not showing you is acting differently. Again as has been requested many times, please show more pertinent code. — Hovercraft Full Of Eels, Aug 15 '15 at 03:34

Stephen C · Accepted Answer · 2015-08-15T03:35:40.920

I have a switch and an if statement, and they are equivalent.

Actually, they are NOT equivalent:

The if version is checking for "yes" or "No". But the switch version of checking for "yes" or "no". Since the checks are case sensitive in both cases, you will get different results if the input is "no" ... or "No".
The two versions check different variables; i.e. yes and yesno. This could make a difference, depending on the context.

Either of these could explain the different behaviour you are seeing.

I thought that yes and yesno would be equal, but they weren't...? Any idea why?

Well, clearly the names are different so they cannot be the same variables.

However, the fact that they are different variables does not necessarily mean that they have different values. It is the values that determine the code's behaviour.

Certainly, if yesno contained a proper "yes" or "no" value and yes contained something else (such as ""), then that would give the behaviour you are observing. (Obviously this is a hypothetical diagnosis. If you want a more concrete answer, show us the relevant code.)

If and Switch same task, different results?

1 Answers1