Calling class methods via class name vs self
class-method, objective-c
Solution
If inside an instance method:
[self runProgram]
in this, `self` means the object instance itself, and thus it will generate a runtime error. You want to use
[[self class] runProgram]
instead.
However, if you call this method from another class method, then
[self runProgram]
is correct, since now `self` refers to the class itself. I'd discourage to use
[Calculator runProgram]
because then subclasses of the class would erroneously call the superclass' (`Calculator`'s) method instead of a possibly overridden method.
Problem
Suppose we have a class named `Calculator`. There's a class method in it, called `runProgram`. If I wanted to call this class method, inside the class's implementation, what would the difference between these two be: ``` [Calculator runProgram] ``` OR ``` [self runProgram] ``` Are these both the same?