#include <iostream>
#include <fstream>
#include <ctime>
#include <cstdlib>
using namespace std;

namespace nsEx22_23{
	int isPrime(int);

	//Exercise 22
	int intEx22(){
		int iin;
		cout << "\nEnter number to check if it is prime:\t";
		cin >> iin;

		if (isPrime(iin) != 0)  //prime
			cout << "\nThe number " << iin << " is Prime\n\n";
		else //non-prime
			cout << "\nThe number " << iin << " is NOT Prime.\n\n";

		cout << "\t\tPress <enter> to continue to problem 23\n";
		cin.get();
		cin.ignore();
		return 0;
	}

	//Exercise 23
	int intEx23(){
		//Prime the file (open and clear)
		ofstream outFile;
		string strFN = "Primes_1-100.txt";
		outFile.open(strFN);
		outFile.clear();

		//Prime Finder
		for (int x = 1; x <= 100; x++){			
			if (isPrime(x) != 0){ //prime
				outFile << x << "\n";
			}
		}
			outFile.close();
			cout << "\t>>> Primes between 1-100 were written to: " << strFN << " <<<\n\n";
			system("pause");
			cout << endl;
			return 0;
	}

	//Prime Checker function
	int isPrime(int num1){
		for (int num2 = 2; num2 <= sqrt(num1); num2++){ // >1 because every number is divisible by 1
			num1 %= num2;
			if ((num1 % num2) == 0) //not prime
				break;
		}
		return num1; //return remainder
	}
}