This a classic OOP (Object Oriented Programming) problem for interview and coding challenge where you will be given a bird interface to implement and egg class to be completed. Here's how I solved it using PHP

Chicken Egg Problem

Add the missing code to Chicken and Egg so the following actoins are completed:

  • Chicken implements the Bird interface.
  • A Chicken lays an egg that will hatch into a new Chicken.
  • Eggs from other types of birds should hatch into a new bird of their parent type.
  • Hatching an egg for the second time throws an Exception

Check problem.php for code template

Output For The Solution.php 

The eggOne from chickenOne hatched & new chickenTwo has borned
The eggTwo from chickenTwo hatched & new chickenThree has borned
Hatching again will cause an exception

PHP Fatal error: Uncaught Exception: The egg already hatched in /Users/myusername/code/chicken_egg.php:30
Stack trace:
#0 /Users/myusername/code/chicken_egg.php(52): Egg->hatch()
#1 {main}
 thrown in /Users/myusername/code/chicken_egg.php on line 30

Fatal error: Uncaught Exception: The egg already hatched in /Users/myusername/code/chicken_egg.php:30
Stack trace:
#0 /Users/myusername/code/chicken_egg.php(52): Egg->hatch()
#1 {main}
 thrown in /Users/myusername/code/chicken_egg.php on line 30