If statement not called with NSStrings equaling each other

Question

Can someone please explain why this code doesn't work? Both Theorem and title are NSStrings, and when displayed in the console, it is clear that they match at some point, but the nslog@"HI" is never printed. Thanks!

if (Theorem==title) {
        NSLog(@"hi");

        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        [defaults setValue:title forKey:@"title"];
        [defaults setValue:info forKey:@"info"];
        [defaults setValue:subInfo forKey:@"subInfo"];
        [defaults synchronize];
    }
    else{
        NSLog(@"%@",Theorem);
        NSLog(@"%@",title);
    }

Answer 1

You must use the isEqualToString: method to compare the value of two strings. Using the == operator just compares the two pointers.

if ([Theorem isEqualToString:title]) {
} else {
}