Is nil and null the same C?
Objective-C builds on C’s representation of nothing by adding nil . nil is an object pointer to nothing. Although semantically distinct from NULL , they are technically equivalent.
What is the difference between nil and null in Swift?
The difference is that while NULL represents zero for any pointer, nil is specific to objects (e.g., id) and Nil is specific to class pointers.
Does nil mean null?
3 Answers. Well, “nil” is the traditional name for the reified concept of “nothing” in Lisp and Smalltalk†. The word “null” is used as an adjective meaning “empty”, as in “the null list,” which is nil. Meanwhile, “null” is traditionally a pointer value in C that signifies the pointer doesn’t point to anything valid.
How does Objective-C handle null values?
The NULL value for Objective-C objects (type id) is nil. While NULL is used for C pointers (type void *). nil = (all lower-case) is a null pointer to an Objective-C object. Nil = (capitalized) is a null pointer to an Objective-C class.
What is difference between null and nil?
In short they all are 0 and nothing else. The difference is that while NULL represents zero for any pointer, nil is specific to objects (e.g., id) and Nil is specific to class pointers.
Why is it nil instead of zero?
According to the Oxford English Dictionary, the first use of the word “love” in English to mean “zero” was to define how a game was to be played, rather than the score in the game itself. Another name for 0 that is used in sports is “nil”. This is derived from the Latin word “nihil”, which means “nothing”.
What is nil in IOS?
nil is an empty value bound/corresponding with an object (the id type in Objective-C).
What is difference between nil and null?
What is nil in data structure?
In programming, nil refers to an empty set or a list containing no entries. In some usages, nil is interchangeable with null. In certain programming languages such as Pascal , Smalltalk , or LISP (list processing), nil represents the absence of an object, or the empty pointer value.
How do I check if a variable is null in Objective C?
If you treat it is a null string like nil , then test (object. length == 0) . object. length will return 0 if object == nil , so this test covers nil objects and strings with length 0.
How do I check if NSString is null in Objective C?
5 Answers
- No need to use isEqual . == works just fine, since [NSNull null] is a singleton.
- Create a category on NSString and include this method: + (BOOL)isEmpty:(NSString *)string {return !
- if (myString == (NSString*)[NSNull null]) if you do not cast it then there is a warning just pointing that out.
What is difference between null and null in Scala?
AnyRef is the supertype of all the reference classes (like String, List, Iterable) in scala. Null is a subtype of all the reference classes. null is its only instance. Nothing is subtype of every other type i.e of reference and value classes.
What’s the difference between null, NIL and null?
All three of these values represent null, or zero pointer, values. The difference is that while NULL represents zero for any pointer, nil is specific to objects (e.g., id) and Nil is specific to class pointers.
Which is an example of a nil in Objective C?
Nilis the literal null value for Objective-C classes, corresponding to the type Class. Since most code doesn’t need variables to reference classes, its use is not common. One example is: Class someClass = Nil; Class anotherClass = [NSString class]; NULLis the literal null value for arbitrary C pointers. For instance,
Which is the null value in Objective C?
6 Answers 6. nil is the literal null value for Objective-C objects, corresponding to the abstract type id or any Objective-C type declared via @interface. For instance: Nil is the literal null value for Objective-C classes, corresponding to the type Class. Since most code doesn’t need variables to reference classes, its use is not common.
What’s the difference between null and void in C?
C style says that NULL is what you use for void *. C++ style typically says that you should just use 0. I typically use the variant that matches the language where the type is declared. NULL is zero typed as void*. One important point you can’t send a message to NULL.