ProjectEulerCPP/Source/Problem17.cpp

//ProjectEuler/C++/Source/Problem17.cpp
//Matthew Ellison
// Created: 10-05-18
//Modified: 07-14-19
//If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
/*
	Copyright (C) 2019  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 <cinttypes>
#include <string>
#include <sstream>
#include "Stopwatch.hpp"
#include "../Headers/Problem.hpp"
#include "../Headers/Problem17.hpp"


int Problem17::TOP_NUM = 1000;

Problem17::Problem17() : Problem("If all the numbers from 1 to 1000 inclusive were written out in words, how many letters would be used?"), letterCount(0){

}

std::string Problem17::makeWord(int num){
	int currentDivider = 1000;
	int currentNum;
	bool teen = false;
	std::string word = "";
	std::string currentWord = "";


	//Start at thousands
	currentNum = num / currentDivider;
	if(currentNum > 0 && num != 0){
		num -= currentNum * currentDivider;
		currentWord = wordHelper(currentNum);
		word += currentWord + " thousand ";
		currentWord = "";
	}

	//Check for hundreds
	currentDivider /= 10;
	currentNum = num / currentDivider;
	if(currentNum > 0 && num != 0){
		num -= currentNum * currentDivider;
		currentWord = wordHelper(currentNum);
		word += currentWord + " hundred ";
		currentWord = "";
	}

	//Insert an and if there is a reason
	if(word != "" && num > 0){
		word += " and ";
	}

	//Check for double digits
	currentDivider /= 10;
	currentNum = num / currentDivider;
	if(currentNum > 0 && num != 0){
		num -= currentNum * currentDivider;
		currentWord = wordHelper(currentNum);
	}
	if(currentWord != ""){
		//For specialty numbers
		if(currentNum == 8){
			word += "eighty ";
		}
		else if(currentNum == 5){
			word += "fifty ";
		}
		else if(currentNum == 4){
			word += "forty ";
		}
		else if(currentNum == 3){
			word += "thirty ";
		}
		else if(currentNum == 2){
			word += "twenty ";
		}
		//For teens
		else if(currentNum == 1){
			if(num == 8){
				word += "eighteen";
				num = 0;
			}
			else if(num == 5){
				word += "fifteen";
				num = 0;
			}
			else if(num == 3){
				word += "thirteen";
				num = 0;
			}
			else if(num == 2){
				word += "twelve";
				num = 0;
			}
			else if(num == 1){
				word += "eleven";
				num = 0;
			}
			else if(num == 0){
				word += "ten";
				num = 0;
			}
			else{
				teen = true;
			}
		}
		//For all other numbers > 30
		else{
			word += currentWord + "ty ";
		}
		currentWord = "";
	}
	//Check for single digits
	currentDivider /= 10;
	currentNum = num / currentDivider;
	if(currentNum > 0 && num != 0){
		num -= currentNum * currentDivider;
		currentWord = wordHelper(currentNum);
		word += currentWord;
		if(teen){
			word += "teen";
		}
	}

	return word;
}

std::string Problem17::wordHelper(int num){
	std::string tempString;
	switch(num){
		case 9: tempString += "nine"; break;
		case 8: tempString += "eight"; break;
		case 7: tempString += "seven"; break;
		case 6: tempString += "six"; break;
		case 5: tempString += "five"; break;
		case 4: tempString += "four"; break;
		case 3: tempString += "three"; break;
		case 2: tempString += "two"; break;
		case 1: tempString += "one"; break;
		default: tempString += "ERROR"; break;
	}
	return tempString;
}

uint64_t Problem17::countLetters(std::string str){
	uint64_t letterCount = 0;
	//Step through every character in the string and count how many letters there are
	for(unsigned int cnt = 0;cnt < str.size();++cnt){
		if(isalpha(str.at(cnt))){
			++letterCount;
		}
	}
	return letterCount;
}

void Problem17::solve(){
	//If the problem has already been solved do nothing and end the function
	if(solved){
		return;
	}

	//Start the timer
	timer.start();

	//Step through every element in nums and get the word representations of the numbers
	for(int cnt = 1;cnt <= TOP_NUM;++cnt){
		std::string words = makeWord(cnt);	//Get the words of each number in turn
		letterCount += countLetters(words);	//Add the number of letters to the running tally
	}

	//Stop the timer
	timer.stop();

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

std::string Problem17::getString() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}
	std::stringstream results;
	results << "The number of letters is " << letterCount;
	return results.str();
}

uint64_t Problem17::getLetterCount() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}
	return letterCount;
}