Weird situation with IF statement

Question

I have the following code:

if (flag == 2 && username1 != username2 && password1 != password2)
{
 alert =[[UIAlertView alloc ] initWithTitle: @"INCORRECT...

Values I have:

flag = 2 , username1 = @“aa“, password1 = @“aa“, username2 = @“aa“, password2 = @“aa“

So the above IF statement should evaluate to false right? Yet for reasons unbeknownst to me, the statements after the IF statement are executed! Any idea why?

Thanks for your input.

Use parenthesis inside the IF statement to override operator precedence rules — Andrea, Sep 04 '14 at 12:13
See http://stackoverflow.com/questions/2592511/string-comparison-in-objective-c — , Sep 04 '14 at 12:13

score 4 · Accepted Answer · answered Sep 04 '14 at 12:14

4

If username1 and the other strings are just char * variables, the pointers can be different even though the content is the same.

In C, you would use strcmp for this but, in ObjC, I think you have to use the -isEqualToString: method, something like:

if ((flag == 2) &&
    (![username1 isEqualToString:username2]) &&
    (![password1 isEqualToString:password2]))

answered Sep 04 '14 at 12:14

paxdiablo

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You were a minute faster - you get my upvote. ;o) – Kai Mattern Sep 04 '14 at 13:12

score 3 · Answer 2 · answered Sep 04 '14 at 12:15

3

To compare the string content instead of the object, use Equal:

if ([string isEqualToString:@"Some String"])
{
    // Do stuff...
}

answered Sep 04 '14 at 12:15

Kai Mattern

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Weird situation with IF statement

2 Answers2