# How do you implement recursion in programming?

Recursion is a programming technique where a function calls itself in order to solve a problem. It can be used to simplify problems that can be broken down into smaller, similar problems.

## Steps

TypeDescription
Identify the base caseThe base case is the simplest form of the problem that can be solved without recursion.
Divide the problem into smaller, similar sub-problemsYou can divide the problem into smaller sub-problems by breaking down the input data into smaller pieces, or by dividing the problem into simpler sub-tasks.
Recursively call the function to solve each sub-problemThe function should call itself with the sub-problems as input, until it reaches the base case.
Combine the results from the sub-problems to form the final solutionAfter the function has returned from each recursive call, you can combine the results to form the final solution.

Here is an example of how you can use recursion to find the factorial of a number:

``````function factorial(n) {
// Base case: If n is 0 or 1, return 1
if (n <= 1) {
return 1;
}

// Divide the problem into smaller sub-problems
var sub_factorial = factorial(n - 1);

// Recursively call the function to solve each sub-problem
return n * sub_factorial;
}

var result = factorial(5);
console.log(result); // Output: 120``````

In this example, the function factorial calculates the factorial of a number n by recursively calling itself with n - 1 as input. The base case is when n is 0 or 1, and the function returns 1. When the function reaches the base case, it returns the result of the calculation, and the results are combined by the previous calls to form the final solution.

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