Day 2 Solution

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>

using namespace std;

struct Coord {
    int x, y;

    Coord(int xIn = 0, int yIn = 0) : x(xIn), y(yIn) {}

    Coord operator+(const Coord &other) {
        return Coord(x + other.x, y + other.y);
    }

    Coord operator=(const Coord &other) {
        x = other.x;
        y = other.y;

        return *this;
    }

    bool legal() {
        return (x >= 0 && x < 3 && y >= 0 && y < 3);
    }

};

int main() {
    fstream in("input.txt");
    string line;

    // const int BUTTON[3][3] = {
    //     {1, 2, 3},
    //     {4, 5, 6},
    //     {7, 8, 9}
    // };
    //
    const char BUTTON[5][5] = {
        {'?', '?', '1', '?', '?'},
        {'?', '2', '3', '4', '?'},
        {'5', '6', '7', '8', '9'},
        {'?', 'A', 'B', 'C', '?'},
        {'?', '?', 'D', '?', '?'}
    };

    // Coord location(1, 1);
    Coord location(2, 2);
    Coord movement;
    while(in >> line) {
        // cout << line << endl;
        for(int i = 0; i < line.size(); i++) {
            if(line.at(i) == 'U') {
                movement = Coord(0, -1);
            }
            else if(line.at(i) == 'R') {
                movement = Coord(1, 0);
            }
            else if(line.at(i) == 'D') {
                movement = Coord(0, 1);
            }
            else if(line.at(i) == 'L') {
                movement = Coord(-1, 0);
            }
            Coord tempLocation = location + movement;
            char button = BUTTON[tempLocation.y][tempLocation.x];
            // if(tempLocation.legal()) {
            if(isalnum(button)) {
                location = tempLocation;
            }
        }
        cout << BUTTON[location.y][location.x];
    }

    return 0;
}