test if a int is prime

test.cpp

#include <iostream>
#include <cmath>

bool isPrime(int n) {
    int m = (int)std::sqrt(n);
    if (m != 2)
        while (m > 2){
            if(n % m == 0)
                return false;
            else
                m--;
        }
    else if (n % m == 0)
        return false;
    else
        return true;
}

int main(int argc, char **argv) {
    int n;
    std::cout << "Please enter a number: " << std::endl;
    std::cin >> n;
    if (isPrime(n) == true)
        std::cout << "The number is prime." << std::endl;
    else
        std::cout << "The number is divisable!" << std::endl;
    return 0;
}