public static int sum(int intSum) {
if (intSum == 1) return 1;
return intSum + sum(intSum - 1);
}The stack
A stack is a Data Structure. You can only take or remove things from the top or bottom.
Methods are placed on a stack. Calls keep stacking in a recursive method until eventually it overflows. This is why we need to call a base case in a Recursive function
Use cases to solve recursion questions
- Trees
- For loops are linear. But iterating though a tree requires splitting
Example question from Jeg
- 11 calls. Returns 6
- the 6th last calls were what returned 1. it’s not 17 (i was confusled)