// A : Parent
@implementation A
-(id) init
{
    // change self here then return it
}
@end A

A *a = [[A alloc] init];

a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self.

-(id) init
{
    id tmp = [super init];
    if(tmp != nil) {
        //do stuff
    }
    return tmp;
}

b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right?

c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right?

sorry, don't have Mac to try, learning theory as for now...