diff --git a/src/Problems.rs b/src/Problems.rs
index 685288d..c39f4b1 100644
--- a/src/Problems.rs
+++ b/src/Problems.rs
@@ -9,3 +9,4 @@ pub mod Answer;
pub mod Problem1;
pub mod Problem2;
pub mod Problem3;
+pub mod Problem4;
diff --git a/src/Problems/Problem4.rs b/src/Problems/Problem4.rs
new file mode 100644
index 0000000..4fad4b8
--- /dev/null
+++ b/src/Problems/Problem4.rs
@@ -0,0 +1,69 @@
+//ProjectEulerRust/src/Problems/Problems4.rs
+//Matthew Ellison
+// Created: 06-14-20
+//Modified: 06-14-20
+//Find the largest palindrome made from the product of two 3-digit numbers
+//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses
+/*
+ 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 .
+*/
+
+
+extern crate myClasses;
+use crate::Problems::Answer::Answer;
+
+
+pub fn getDescription() -> String{
+ "Find the largest palindrome made from the product of two 3-digit numbers".to_string()
+}
+
+pub fn solve() -> Answer{
+ let START_NUM = 100;
+ let END_NUM = 999;
+ //Start the timer
+ let mut timer = myClasses::Stopwatch::Stopwatch::new();
+ timer.start();
+
+ let mut palindromes = Vec::::new();
+
+ //Start at the first 3-digit number and check every one up to the last 3-digit number
+ for firstNum in START_NUM..END_NUM{
+ //You can start at the location of the first number because everything before that has already been tested. (100 * 101 == 101 * 100)
+ for secondNum in firstNum..END_NUM{
+ //Get the product of the numbers
+ let product = firstNum * secondNum;
+ //Change the number into a string
+ let productString: String = product.to_string();
+ //Reverse the string
+ let reverseString: String = productString.chars().rev().collect();
+
+ //If the number and it's reverse are the same it is a palindrome so add it to the list
+ if(productString == reverseString){
+ palindromes.push(product);
+ }
+ //If it's not a palindrome ignore it and move to the next number
+ }
+ }
+
+ //Stop the timer
+ timer.stop();
+
+ //Sort the palindromes so that the last one is the largest
+ palindromes.sort();
+
+ //Return the results
+ return Answer::new(format!("The largest palindrome is {}", palindromes[palindromes.len() - 1]), timer.getString());
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 3489ccd..6a9ed89 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,7 +16,7 @@ mod Problems;
#[derive(PartialEq)]
enum Selections{EMPTY, SOLVE, DESCRIPTION, LIST, EXIT, SIZE}
-static problemNumbers: [u32; 4] = [0, 1, 2, 3];
+static problemNumbers: [u32; 5] = [0, 1, 2, 3, 4];
fn main(){
let mut selection = Selections::EMPTY;
@@ -125,6 +125,10 @@ fn solveProblem(problemNumber: u32){
println!("{}", Problems::Problem3::getDescription());
println!("{}", Problems::Problem3::solve());
}
+ else if(problemNumber == 4){
+ println!("{}", Problems::Problem4::getDescription());
+ println!("{}", Problems::Problem4::solve());
+ }
}
fn descriptionMenu(){
//Give some extra space to print the description
@@ -159,6 +163,9 @@ fn printDescription(problemNumber: u32){
else if(problemNumber == 3){
println!("{}", Problems::Problem3::getDescription());
}
+ else if(problemNumber == 4){
+ println!("{}", Problems::Problem4::getDescription());
+ }
}
fn getProblemNumber() -> u32{
println!("Enter a problem number: ");