Explain the concept of recursive calls in programming

A recursive call is when a function calls itself to solve a problem. Recursion is typically used to break down a complex problem into simpler subproblems of the same type.

Example: calculating the factorial of a number n (n!) — the product of all numbers from 1 to n.

def factorial(n):
    if n == 0 or n == 1:
        return 1
    else:
        return n * factorial(n - 1)

Here, the factorial function calls itself with a reduced argument until it reaches the base case (n == 0 or 1), after which it starts returning results back through the chain of calls.

It is important for a recursive function to have a base case, otherwise, the calls will be infinite and lead to a stack overflow.