239: Highlights

• Recursive functions work by calling themselves to solve subproblems until the subproblems are simple enough for them to solve directly.
• The portion of a recursive function that handles the simplest cases is called the base part; the portion that transforms more complex cases is called the recursion part.
• If you want to solve a difficult problem, then try to break it up into simpler subproblems.
• If you are writing a recursive function, then your function must handle the simplest cases, and must break down every other case into the simplest cases.
• If your recursive function is to count down a number, then you may be able to instantiate the following pattern:

  int function name (int n) { 
    if (n == 0) 
      return result for n equal 0; 
    else 
      return combination operand 
             combination operator 
             function name (n - 1); 
  }