/**
Shade Alabsa
isPrime
Cycles through the numbers 1-100 and uses isPrime to calculate if a number is prime. This is a very rudimentary algorithm to fix it but I didn't want to figure our arrays in c++ right now to implement a proper sieve of eratosthenes algorithm.

*/
#include <iostream>
#include <fstream>
using namespace std;

//Calcaulates if a number is prime by mod division
bool isPrime(int);

int main(){

    ofstream prime_list; //creates a file stream to write the data to
    prime_list.open("prime_list.txt"); //creates a file called prime_list.txt
    prime_list << "List of Prime Numbers under 100. \n"; //headed for prime_list file
    prime_list << "1\n"; //we know 1-3 are all prime numbers so might as well and add them now so we can cycle through less numbers.
    prime_list << "2\n";
    prime_list << "3\n";

    for(int i = 5;i<=100;i+=2){ //we start cycling through the numbers. We started at 5 since we know 1-3 are all primes and any even number is composite. That's also why we add 2 to every prime so we can skip it
        if(isPrime(i)){
            prime_list << i << endl; //if the number is prime it writes it to the file
        }
    }

    prime_list.close();
    return 0;
}

/**
Calculates the midpoint of the number passed it, any number won't be divisible by anything that is equal to half of it. Then it cycles from 2, just as a precaution or if you want to reuse this function for later, to see if a
number can divide into the passed in number evenly. Takes 1 argument, the number we are testing to see if it's prime, and returns a boolean value saying it's a prime or not.
*/
bool isPrime(int num){
    int mid = num /2 +1;
    bool prime = true;

    for(int i = 2; i<= mid;i++){
        if(num % i == 0){
            prime = false;
        }
    }

    return prime;
}