Which statement describes the base case in a recursive algorithm?

Which statement describes the base case in a recursive algorithm?

• A. A condition under which the recursive calls stop.
• B. The initial input value.
• C. A function that calls itself.
• D. A memory allocation in the heap.

Answer: (A)

The main idea here is what ends a recursive process. The base case is the condition that stops making further recursive calls and returns a simple, direct result. This termination point prevents infinite recursion and provides an easy instance the algorithm can solve without calling itself again. For example, when calculating factorial, you stop when the input reaches 0 or 1 and return 1. When summing a list, you stop when the list is empty and return 0. The other statements don’t capture that stopping condition: starting value is just where you begin, the act of a function calling itself describes the recursion in general, and memory allocation in the heap is unrelated to how the recursion proceeds.

The main idea here is what ends a recursive process. The base case is the condition that stops making further recursive calls and returns a simple, direct result. This termination point prevents infinite recursion and provides an easy instance the algorithm can solve without calling itself again. For example, when calculating factorial, you stop when the input reaches 0 or 1 and return 1. When summing a list, you stop when the list is empty and return 0. The other statements don’t capture that stopping condition: starting value is just where you begin, the act of a function calling itself describes the recursion in general, and memory allocation in the heap is unrelated to how the recursion proceeds.