AdventOfCode-2023/day01-easy/src/main.zig

const std = @import("std");

pub fn main() !void {
    const stdout = std.io.getStdOut().writer();

    const raw_in = std.io.getStdIn();
    var buffered_reader = std.io.bufferedReader(raw_in.reader());
    var reader = buffered_reader.reader();

    var result: u32 = 0;
    var line_buffer: [1000]u8 = undefined;
    while (try reader.readUntilDelimiterOrEof(&line_buffer, '\n')) |line| {
        var firstDigit: u8 = 0;
        var lastDigit: u8 = 0;
        for (0..line.len) |i| {
            const char = line[i];
            if (char >= '0' and char <= '9') {
                firstDigit = char - '0';
                break;
            }
        }
        for (0..line.len) |i| {
            const index = line.len - i - 1;
            const char = line[index];
            if (char >= '0' and char <= '9') {
                lastDigit = char - '0';
                break;
            }
        }

        result += firstDigit * 10 + lastDigit;
    }
    try stdout.print(
        "{d}\n",
        .{result},
    );
}