Recursion vs Iteration When Each Wins in DSA Typescript - Build Both Approaches

Recursion vs Iteration: When Each Wins

📖 Scenario: Imagine you are helping a friend understand two ways to solve problems: recursion and iteration. You will create simple examples to see how each works and when one might be better than the other.

🎯 Goal: Build two functions in TypeScript: one using recursion and one using iteration to calculate the factorial of a number. Learn how each method works and print the results.

📋 What You'll Learn

Create a variable called num with the value 5.

Create a recursive function called factorialRecursive that takes a number and returns its factorial.

Create an iterative function called factorialIterative that takes a number and returns its factorial.

Print the results of both functions for the number num.

💡 Why This Matters

🌍 Real World

Understanding recursion and iteration helps in solving many programming problems like searching, sorting, and navigating data structures.

💼 Career

Many software engineering roles require knowledge of recursion and iteration to write efficient and clean code.

1

Set up the number to calculate factorial

Create a variable called num and set it to 5.

DSA Typescript

# Create a variable called num and set it to 5
// Your code here

Hint

Use const num = 5; to create the number.

2

Write the recursive factorial function

Create a recursive function called factorialRecursive that takes a parameter n and returns 1 if n is 0, otherwise returns n * factorialRecursive(n - 1).

DSA Typescript

const num = 5;

// Write the recursive function factorialRecursive here
// Your code here

Hint

Use a function that calls itself with n - 1 until n is 0.

3

Write the iterative factorial function

Create an iterative function called factorialIterative that takes a parameter n, uses a for loop from 1 to n, multiplies the numbers, and returns the result.

DSA Typescript

const num = 5;

function factorialRecursive(n: number): number {
    if (n === 0) {
        return 1;
    } else {
        return n * factorialRecursive(n - 1);
    }
}

// Write the iterative function factorialIterative here
// Your code here

Hint

Use a loop to multiply numbers from 1 to n and return the product.

4

Print the factorial results

Print the result of factorialRecursive(num) with the message "Recursive factorial of 5:" and the result of factorialIterative(num) with the message "Iterative factorial of 5:".

DSA Typescript

const num = 5;

function factorialRecursive(n: number): number {
    if (n === 0) {
        return 1;
    } else {
        return n * factorialRecursive(n - 1);
    }
}

function factorialIterative(n: number): number {
    let result = 1;
    for (let i = 1; i <= n; i++) {
        result *= i;
    }
    return result;
}

// Print the factorial results below
// Your code here

Hint

Use console.log to print the messages and results.