Recursion

• Recursion The ability of a subprogram to call itself

• Each recursive solution has at least two cases

• • Base case The case to which we have an answer
  • General case The case that expresses the solution in terms of a call to itself with a smaller version of the problem

• For example, the factorial of a number is defined as the number times the product of all the numbers between itself and 0:

• N! = N * (N  1)!