Question

How do you allocate an object?

Answers

a. MyClass *obj = malloc(sizeof(MyClass));
b. MyClass *obj = [MyClass alloc];
c. MyClass *obj = alloc(MyClass);
d. MyClass *obj = [MyClass new];
e. None of the above.

I’m thinking b or may be d. What do you think?

Answer 1

a. MyClass *obj = malloc(sizeof(MyClass));

This is just wrong. An objective-C object has a specific structure that malloc cannot make. This will NOT create a valid objective-C object.

b. MyClass *obj = [MyClass alloc];

This is the proper way to allocate an object. However all objective-c object must be passed some kind of -init message before it can be used.

c. MyClass *obj = alloc(MyClass);

No.

d. MyClass *obj = [MyClass new];

This is actually the same as [[MyClass alloc] init]. However since the user cannot choose which initializer to use when allocating the new object, most books recommending using the alloc/init method of creating a new object instead of this.