JavaScript Programming Fundamentals

Introduction

In this lab, we will dive into the world of JavaScript programming and learn how to write efficient and effective code. Through a series of hands-on exercises and challenges, you will gain a solid understanding of fundamental programming concepts such as variables, functions, loops, and conditional statements. By the end of this lab, you will have the skills and confidence to tackle real-world programming problems using JavaScript.

Skills Graph

Binomial Coefficient Calculation

To calculate the number of ways to choose k items from n items without repetition and without order, you can use the following JavaScript function:

const binomialCoefficient = (n, k) => {
  if (Number.isNaN(n) || Number.isNaN(k)) return NaN;
  if (k < 0 || k > n) return 0;
  if (k === 0 || k === n) return 1;
  if (k === 1 || k === n - 1) return n;
  if (n - k < k) k = n - k;
  let res = n;
  for (let j = 2; j <= k; j++) res *= (n - j + 1) / j;
  return Math.round(res);
};

To use the function, open the Terminal/SSH and type node. Then, call the function with the desired values. For example:

binomialCoefficient(8, 2); // 28

To ensure the function works correctly, you can follow these steps:

1. Use Number.isNaN() to check if any of the two values is NaN.
2. Check if k is less than 0, greater than or equal to n, equal to 1 or n - 1 and return the appropriate result.
3. Check if n - k is less than k and switch their values accordingly.
4. Loop from 2 through k and calculate the binomial coefficient.
5. Use Math.round() to account for rounding errors in the calculation.

Summary

Congratulations! You have completed the Binomial Coefficient lab. You can practice more labs in LabEx to improve your skills.