iOS nil null nil nsnull difference

The difference between nil, nil, NULL, Nsnull

NIL: A null pointer to an object

Nil: A null pointer to a class

NULL: null pointer to other types (such as base type, C type)

NSNull: Usually represents a null value in a collection

Example:

Nsurl *url = nil;

Class class = Nil;

int *pointerint = NULL;

Nsarray *array = [Nsarray arraywithobjects:[[nsobject alloc] init], [NSNull null], [[NSObject alloc] init], [[NSObject All OC] init], nil];

Why is the empty object in the above array not directly with nil?

If nil is used, it becomes nsarray *array = [Nsarray arraywithobjects:[[nsobject alloc] init], nil, [[NSObject alloc] init], [[NSObject A Lloc] [init], nil];, then the array will end in the second position. printing [array Count] will display 1 instead of 4.

So [NSNull null] can usually be used as a placeholder for an array, thus the count of the array is calculated accurately

iOS nil null nil nsnull difference