Question

In the following code, I passed the “1.3f” to printFloat, but it was the wrong value (in this case, -2.000000) after was “f” received. And there is a warning that “AppDelegate may not respond to -printFloat:”

Where did I get it wrong?

- (void)applicationDidFinishLaunching:(UIApplication *)application{
    // Override point for customization after application launch
    [window makeKeyAndVisible];
    [self printFloat:1.3f];
}

- (void)printFloat:(float)f {
    NSLog(@"%f",f);
}

Answer 1

You can easily resolve both your problems by adding the method prototype into the header file (<sameName>.h):

- (void)printFloat:(float)f;