Objective-C Basics stage 5, task 3/4

Hey Bradan,

This is the code that was accepted:

NSNumber *foxtrot = [[NSNumber alloc] initWithInt:24]; NSLog(@"foxtrot %@", foxtrot); NSNumber *planck = [NSNumber numberWithDouble:6.626];

Thank you for your guidance!

Ethan,

It appears that you are trying to initialize "planck" with an integer. 6.626 is a floating number.

Regardless, in this challenge, it does not require you to alloc or init for "planck", so try dropping the square brackets and the alloc/init.

Hope this helps!

That's strange. I got it with

NSNumber *planck = @6.626;

Glad you got it!

I've noticed a few spots where it wasn't necessary to use the exact code they were looking for, just to provide the correct output. I'm guessing that:

NSNumber *planck = [NSNumber numberWithDouble:6.626];

AND

NSNumber *planck = @6.626;

provide the same output?

Whenever you use the @ symbol, it is a shortcut to creating an object. The @ symbol is an indicator to the compiler. When the compiler comes across it in your code it is then instructed to convert it to object allocation and initialization.

Here's what each NSNumber literal is analogous to:

  // character literals.
  NSNumber *theLetterZ = @'Z';          // equivalent to [NSNumber numberWithChar:'Z']

  // integral literals.
  NSNumber *fortyTwo = @42;             // equivalent to [NSNumber numberWithInt:42]
  NSNumber *fortyTwoUnsigned = @42U;    // equivalent to [NSNumber numberWithUnsignedInt:42U]
  NSNumber *fortyTwoLong = @42L;        // equivalent to [NSNumber numberWithLong:42L]
  NSNumber *fortyTwoLongLong = @42LL;   // equivalent to [NSNumber numberWithLongLong:42LL]

  // floating point literals.
  NSNumber *piFloat = @3.141592654F;    // equivalent to [NSNumber numberWithFloat:3.141592654F]
  NSNumber *piDouble = @3.1415926535;   // equivalent to [NSNumber numberWithDouble:3.1415926535]

  // BOOL literals.
  NSNumber *yesNumber = @YES;           // equivalent to [NSNumber numberWithBool:YES];
  NSNumber *noNumber = @NO;             // equivalent to [NSNumber numberWithBool:NO];