Prime Number Checking Algorithm

User Input Analysis

The task is to design an algorithm to determine whether a given number is a prime number.

Pseudo Code

Algorithm to Check Prime Number:

1. Input: a number num
2. Initialize a boolean variable isPrime to true
3. Check if num is less than 2, if true, set isPrime to false
4. Iterate from 2 to the square root of num:
   • Check if num is divisible by the current divisor, if true, set isPrime to false and break the loop
5. Output num as prime if isPrime is still true; otherwise, output num as not prime

function isPrimeNumber(num):
    isPrime = true
    if num < 2:
        isPrime = false
    else:
        for i from 2 to square root of num:
            if num % i == 0:
                isPrime = false
                exit loop
    if isPrime is true:
        output "num is a prime number"
    else:
        output "num is not a prime number"

Input: num   // Number to check for primality
Call isPrimeNumber(num)

Explanation

• The algorithm takes a number as input and iterates to check if the number is divisible by any number from 2 to its square root.
• If the number is found to be divisible, it is marked as not prime; otherwise, it is marked as prime.
• The algorithm efficiently determines the primality of the given number.