Question

Are there any difference between following ways to init self?

First:

- (id)init {
   self = [super init];
   if (self) {

   }
   return self;
}

Second:

- (id)init {
   if (self = [super init]) {

   }
   return self;
}

I like to use second way to init self. But I often see the first way when I create a new class by Xcode, it will generate those codes automatically. I am afraid the second way will make some errors in some condition which I don’t know.

Answer 1

Nope, they are the same.

The second method is just missing out the first assignment of self

Another way you might come across is this:

 - (id)init  {  
    if (!(self = [super init])) {
        return nil; // Bail!
    }
    // Further initialisation   

    return self;
}

This puts the exceptional condition in the if statement, and keeps the code that you expect to run normally (the Happy Path) closer to the left margin.