Prime Number Checker

#include <iostream>
using namespace std;

bool isPrime(int num) {
    if (num <= 1) {
        return false;
    }
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            return false;
        }
    }
    return true;
}

int main() {
    int number;
    cout << "Enter a number: ";
    cin >> number;

    if (isPrime(number)) {
        cout << number << " is a prime number." << endl;
    } else {
        cout << number << " is not a prime number." << endl;
    }

    return 0;
}

This code includes the necessary header files and defines a function isPrime to check if a given number is prime. The function takes an integer as input and returns a boolean value (true if the number is prime and false otherwise).

• isPrime function:
• It checks if the input number is less than or equal to 1, returning false in such cases.
• It iterates from 2 up to the square root of the input number.
• Inside the loop, it checks if the number is divisible by i. If it is, the number is not prime and false is returned.

• If no divisors are found within the loop, the function returns true, indicating the number is prime.

• main function:

• It prompts the user to enter a number.
• Reads the input number using cin.
• Calls the isPrime function with the entered number.
• Prints a message stating whether the number is prime or not based on the returned value from isPrime.

The code utilizes a basic prime number checking algorithm that iterates up to the square root of the number to determine its primality, efficiently avoiding unnecessary iterations beyond that point.