//ProjectEuler/ProjectEulerCPP/Source/Problem5.cpp
//Matthew Ellison
// Created: 09-28-18
//Modified: 07-09-20
//What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
/*
	Copyright (C) 2020  Matthew Ellison

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/


#include <vector>
#include <cinttypes>
#include <string>
#include <sstream>
#include "Stopwatch.hpp"
#include "../Headers/Problem.hpp"
#include "../Headers/Problem5.hpp"


//Constructor
Problem5::Problem5() : Problem("What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?"), smallestNum(0){
}

//Solve the problem
void Problem5::solve(){
	//If the problem has already been solved do nothing and end the function
	if(solved){
		return;
	}
	//Setup your variables
	bool numFound = false;	//Used to determine if the number has been found

	//Start the timer
	timer.start();

	//Start at 20 because it must at least be divisible by 20. Increment by 2 because it must be an even number to be divisible by 2
	//Loop through every even number starting at 20
	int currentNum = 20;
	while((currentNum > 0) && (!numFound)){
		//Start by assuming you found the number (because we throw a flag if we didn't find it)
		numFound = true;
		//Step through every number from 1-20 seeing if the current number is divisible by it
		for(int divisor = 1;divisor <= 20;++divisor){
			//If it is not divisible then throw a flag and start looking at the next number
			if((currentNum % divisor) != 0){
				numFound = false;
				break;
			}
		}
		//If you didn't find the correct number then increment by 2
		if(!numFound){
			currentNum += 2;
		}
	}

	smallestNum = currentNum;

	//Stop the timer
	timer.stop();

	//Save the results
	result << "The smallest positive number evenly divisible by all numbers 1-20 is " << smallestNum;

	//Throw a flag to show the problem is solved
	solved = true;
}

//Reset the problem so it can be run again
void Problem5::reset(){
	Problem::reset();
	smallestNum = 0;
}

//Returns the requested number
int Problem5::getNumber() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw Unsolved();
	}
	return smallestNum;
}