Find prime numbers 0-100 in JavaScript: Step-by-step guide

Introduction

Finding prime numbers in a given range is a common task in programming. In this step-by-step guide, we will walk you through the process of finding prime numbers between 0 and 100 using JavaScript.

Step 1: Understanding Prime Numbers

Prime numbers are numbers that are only divisible by 1 and themselves. For example, 2, 3, 5, 7, 11 are prime numbers. To find prime numbers between 0 and 100, we need to check if each number in the range is divisible by any number other than 1 and itself.

Step 2: Writing the JavaScript Function

To write the function, we will use a for loop to iterate through each number in the range. Then, we will use another for loop to check if the number is divisible by any number other than 1 and itself.

Here is the code for the function:

function findPrimes() {
  let primes = [];
  for (let i = 2; i <= 100; i++) {
    let isPrime = true;
    for (let j = 2; j < i; j++) {
      if (i % j === 0) {
        isPrime = false;
        break;
      }
    }
    if (isPrime) {
      primes.push(i);
    }
  }
  return primes;
}

Let's go through the code. We first create an empty array to store the prime numbers. Then, we use a for loop to iterate through each number in the range from 2 to 100. Inside the loop, we set a variable isPrime to true, assuming that the current number is prime.

Next, we use another for loop to check if the current number is divisible by any number other than 1 and itself. If it is, we set isPrime to false and break out of the loop.

Finally, if the current number is prime (isPrime is still true), we push it to the primes array.

The function returns the primes array.

Step 3: Testing the Function

To test the function, we can simply call it and log the result to the console:

console.log(findPrimes());

This should output the following array:

[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]

Conclusion

In this step-by-step guide, we have shown you how to find prime numbers between 0 and 100 using JavaScript. By using a for loop and checking for divisibility, we were able to create a simple and efficient function.