Overriding init in subclass

Question

In Objective-C, is it necessary to override all inherited constructors of a subclass to add custom initialization logic?

For example, would the following be correct

Answer 1

In case of using Interface Builder, the one is called is :

- (id)initWithCoder:(NSCoder *)coder
{
    self = [super initWithCoder:coder];
    if (self) {
       //do sth
    }
    return self;
}