Question

I’m an experienced programmer so this cryptic behaviour is a total mystery to me.

I have a simple if-statement that should only be entered when exactly two boolean variables are false. However, the if-statement is for some reason entered when only one of them is false.

My code looks like this:

BOOL connected = [self connected];

NSLog(@"Connected to the internet: %@", connected ? @"YES" : @"NO");

BOOL notConnectedMessageShown = ((FOLDAppDelegate *)[[UIApplication sharedApplication] delegate]).notConnectedMessageShown;

NSLog(@"notConnectedMessageShown: %@", notConnectedMessageShown ? @"YES" : @"NO");

if (!connected && !notConnectedMessageShown);
{
    NSLog(@"Entering if statement");
}

And the NSLogprints the following:

"Connected to the internet: YES"
"notConnectedMessageShown: NO"
"Entering if statement"

I really do not understand. Since the first variable is truein the first place, the entire if-statement should be skipped according to my programming skills?

Does anyone have an idea of what is going on here?

Answer 1

You have a semicolon at the end of your if

if (!connected && !notConnectedMessageShown);  <<--- this ; is wrong

This way the block for a “true” condition is simply empty, and your code always enters the block right after it.

It should be this:

if (!connected && !notConnectedMessageShown)  <<-- see here
{
   NSLog(@"Entering if statement");
}