title: Class Factory Methods implementation
body: <p>So I am working my way through the Apple documentation of objective-C (before jumping into iphone development). One of the exercises states that I should create a designated initializer  (with 3 params) and suitable factory method. </p>
  
  <p>Now I did this based on my understanding but I am unable to implement the factory method because I dont know if I should use alloc and init within its implementation or not?</p>
  
  <p>the exercise: </p>
  
  <blockquote>
    <p>Declare and implement a new designated initializer used to create an
    XYZPerson using a specified first name, last name and date of birth,
    along with a suitable class factory method. Don’t forget to override
    init to call the designated initializer.</p>
  </blockquote>
  
  <p>The code:</p>
  
  <pre><code>//.h 
  
  -(id)initWithNameAndDob:(NSString *)fName last:(NSString *)lName birth:(NSDate *) dob;
  
  //.m
  -(id)initWithNameAndDob:(NSString *)fName last:(NSString *)lName birth:(NSDate *)dob{
      self = [super init];
      return [self initWithNameAndDob:fName last:lName birth:dob];
  }
  </code></pre>
  
  <p>something missing in implementation?</p>
  
  <p>thank you,</p>