Added solution to problem 19

ProblemSelection.ts

@@ -42,11 +42,12 @@ import { Problem15 } from "./Problems/Problem15";
 import { Problem16 } from "./Problems/Problem16";
 import { Problem17 } from "./Problems/Problem17";
 import { Problem18 } from "./Problems/Problem18";
+import { Problem19 } from "./Problems/Problem19";
 
 
 export class ProblemSelection{
 	//Holds the valid problem numbers
-	public static PROBLEM_NUMBERS: number[] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18];
+	public static PROBLEM_NUMBERS: number[] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19];
 
 	//Returns the problem corresponding to the given problem number
 	public static getProblem(problemNumber: number): Problem{
@@ -70,6 +71,7 @@ export class ProblemSelection{
 			case 16: problem = new Problem16(); break;
 			case 17: problem = new Problem17(); break;
 			case 18: problem = new Problem18(); break;
+			case 19: problem = new Problem19(); break;
 		}
 		return problem;
 	}

Problems/Problem19.ts

@@ -0,0 +1,214 @@
+//ProjectEulerTS/Problems/Problem18.ts
+//Matthew Ellison
+// Created: 04-06-21
+//Modified: 04-06-21
+//How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
+/*
+You are given the following information, but you may prefer to do some research for yourself.
+1 Jan 1900 was a Monday.
+Thirty days has September,
+April, June and November.
+All the rest have thirty-one,
+Saving February alone,
+Which has twenty-eight, rain or shine.
+And on leap years, twenty-nine.
+A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
+*/
+//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/typescriptClasses
+/*
+	Copyright (C) 2021  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/>.
+*/
+
+
+import { Unsolved } from "../Unsolved";
+import { Problem } from "./Problem";
+
+
+//An easier way to signal day of the week
+enum DAYS {SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FIRDAY, SATURDAY, NUMBER_OF_DAYS, ERROR};
+
+
+export class Problem19 extends Problem{
+	//Variables
+	//Static variables
+	private static START_YEAR: number = 1901;	//The first year we are going to test
+	private static END_YEAR: number = 2000;		//The last year we are going to test
+	//Instance variables
+	private totalSundays: number;	//Keep track of the number of sundays
+
+	//Functions
+	//Constructor
+	public constructor(){
+		super(`How many Sundays fell on the first of the month during the twentieth century (1 Jan ${Problem19.START_YEAR} to 31 Dec ${Problem19.END_YEAR})?`);
+		this.totalSundays = 0;
+	}
+	//Operational functions
+	//Solve the problem
+	public solve(): void{
+		//If the problem has already been solved do nothing and end the function
+		if(this.solved){
+			return;
+		}
+
+		//Start the timer
+		this.timer.start();
+
+		//Run for all years 1901-2000
+		for(let year = Problem19.START_YEAR;year <= Problem19.END_YEAR;++year){
+			//Run for all months in the year
+			for(let month = 1;month <= 12;++month){
+				let day: DAYS = this.getDay(month, 1, year);
+				if(day == DAYS.ERROR){
+					console.log("There was an error with the day");
+				}
+				else if(day == DAYS.SUNDAY){
+					++this.totalSundays;
+				}
+			}
+		}
+
+		//Stop the timer
+		this.timer.stop();
+
+		//Throw a flag to show the problem is solved
+		this.solved = true;
+	}
+	//Return the day of the week that the data you pass into it is on
+	private getDay(month: number, day: number, year: number): DAYS{
+		//Make sure the numbers are within propper bounds
+		if((month < 1) || (month > 12) || (day < 1) || (day > 31) || (year < 1)){
+			return DAYS.ERROR;
+		}
+		let numDays: number = 0;
+		let currentYear: number = 1;
+		let currentMonth: number = 1;
+		let currentDay: number = DAYS.SATURDAY;
+		--day;
+
+		//Add the correct number of days for every year
+		while(currentYear < year){
+			if(this.isLeapYear(currentYear)){
+				numDays += 366;
+			}
+			else{
+				numDays += 365;
+			}
+			++currentYear;
+		}
+		//Add the correct number of days for every month
+		while(currentMonth < month){
+			switch(currentMonth){
+				case  1:
+				case  3:
+				case  5:
+				case  7:
+				case  8:
+				case 10:
+				case 12: numDays += 31; break;
+				case  4:
+				case  6:
+				case  9:
+				case 11: numDays += 30; break;
+				case  2:
+					if(this.isLeapYear(currentYear)){
+						numDays += 29;
+					}
+					else{
+						numDays += 28;
+					}
+					break;
+			}
+			++currentMonth;
+		}
+		//Account for the weird year of 1752
+		if(year > 1752){
+			numDays -= 11;
+		}
+		else if(year == 1752){
+			if(month > 9){
+				numDays -= 11;
+			}
+			else if(month == 9){
+				if(day >= 14){
+					numDays -= 11;
+				}
+				else if((day > 2) && (day < 14)){
+					console.log("Hit 1752 error");
+					return DAYS.ERROR;
+				}
+			}
+		}
+		//Add the correct number of days for every day
+		numDays += day;
+
+		currentDay += numDays;
+		currentDay = currentDay % DAYS.NUMBER_OF_DAYS;
+		switch(currentDay){
+			case DAYS.SUNDAY: return DAYS.SUNDAY;
+			case DAYS.MONDAY: return DAYS.MONDAY;
+			case DAYS.TUESDAY: return DAYS.TUESDAY;
+			case DAYS.WEDNESDAY: return DAYS.WEDNESDAY;
+			case DAYS.THURSDAY: return DAYS.THURSDAY;
+			case DAYS.FIRDAY: return DAYS.FIRDAY;
+			case DAYS.SATURDAY: return DAYS.SATURDAY;
+			default:	console.log("Hit default error"); return DAYS.ERROR;
+		}
+	}
+	//Returns true if the year passed to it is a leap year
+	private isLeapYear(year: number): boolean{
+		if(year < 1){
+			return false;
+		}
+		else if((year % 100) == 0){
+			//This rule only applies at and after 1800
+			if(year <= 1700){
+				return true;
+			}
+			else if((year % 400) == 0){
+				return true;
+			}
+		}
+		else if((year % 4) == 0){
+			return true;
+		}
+		return false;
+	}
+	//Reset the problem so it can be run again
+	public reset(): void{
+		super.reset();
+		this.totalSundays = 0;
+	}
+	//Gets
+	//Returns the result of solving the problem
+	public getResult(): string{
+		if(!this.solved){
+			throw new Unsolved();
+		}
+		return `There are ${this.totalSundays} Sundays that landed on the first of the months from ${Problem19.START_YEAR} to ${Problem19.END_YEAR}`;
+	}
+	//Returns the total sundays that were asked for
+	public getTotalSundays(): number{
+		if(!this.solved){
+			throw new Unsolved();
+		}
+		return this.totalSundays;
+	}
+}
+
+/* Results:
+There are 171 Sundays that landed on the first of the months from 1901 to 2000
+It took an average of 4.314 milliseconds to run this problem through 100 iterations
+*/