Printing weird things (Exercises 1 & 4)

Keep a stack of method calls. Write return points and the value of all local variables.  

Example:  see recursive above

Returning values like 2*f(n-1)  (Exercises 2 & 3)

For the recursive case, write the method calls that grow down.   

2*f(n-1)          2*32 = 64

      \           /

    2*f(2)       2*16 = 32

        \       /

       2*f(1)  2*8 = 16

           \  /

            8   

assume if (n==1) return 4  

Writing recursive functions given the recursive definitions (Exercises 6, 7, 8, and 9 )

This may be the easiest. Recursive definitions have the base and recursive cases listed. Translate to Java
  Example:  power(x, n) = x * power(x, n-1);

Writing recursive functions even though they could use a loop. Exercises 10 through 18

Handle the base case(s). Make sure each recursive call increases or decreases an  argument to reach a base case.  Example

Example:  print all evens from start to end

Recursion with arrays Exercises 11-17

You need to go up to length-1 or down to 0 or –1. Let recursion take an index up or down. May need a private helper method to add arguments .

   Example:  find range in an array

Recursion with linked structures (section exercise)

Base case: ref == null.  Let recursion take you to the next node with recCall(ref.next)  
   Example:  toArray for a linked listed of Strings

No trees on Quiz 5, 30-March-2007