Steps to write Recursive methods / procedures

Step 1. Find and write the stopping condition

Step 2. Write the recursive part of the method

Another real life recursion Example:

Doing dishes:


 DoDishes{
        // Step 1.
	if (the sink is empty){
            do nothing;
        }
             
        else{ 
             // Step 2.              
              wash one dish;
             find somebody to doDishes;
       }            
 }

How to design a recursive method:

Use a solution to a smaller or easier version of the problem to arrive at the solution to your problem

This step leads to a recursive call.
Usually laziness can be an inspiration at this step.

Know when the problem is small enough to solve directly.

This step leads to termination code
Laziness can help here too. Ask, What is the easiest version of the problem to solve?

Write a recursive solution to the summation problem:

public int sum(int n){
     int result;
     if (n==1){
          result = 1;
     }
     else{
         result = n + sum(n-1);
     }
   return result;
}