recursion in C language

Recursion is a powerful and essential concept that allows a function to call itself directly or indirectly to solve a problem by breaking it down into smaller instances of the same problem.

A recursive function consists of two parts:

1.Base Case :A condition that specifies the simplest case where the function does not call itself again. It prevents the recursion from continuing indefinitely and provides a termination condition.

2.Recursive Case :The part of the function where it calls itself with a smaller instance of the problem. This allows the function to work on a smaller part of the problem until it reaches the base case.

Here's an example of a recursive function to calculate the factorial of a number:

    
     #include <stdio.h>
     int factorial(int n) { 
        if (n == 0 || n == 1) 
        return 1; 
        else 
        return n * factorial(n - 1); 
        } 

        int main() { 
        int num = 5; 
        printf("Factorial of %d is %d\n", num, factorial(num)); 
        return 0; 
        } 

        Output: 
        Factorial of 5 is 120 
                                    
    
    

In this example, the 'factorial' function is a recursive function that calculates the factorial of a given number `n`. It calls itself with a smaller value (`n - 1`) until it reaches the base case (`n == 0` or `n == 1`), where the recursion stops