Source code in the zig programming language

const std = @import("std");

fn levenshtein(s: []const u8, t: []const u8) usize {
    // If either string is empty, difference is inserting all chars
    // from the other
    if (s.len == 0) return t.len;
    if (t.len == 0) return s.len;

    // If last letters are the same, the difference is whatever is
    // required to edit the rest of the strings
    if (s[s.len - 1] == t[t.len - 1])
        return levenshtein(s[0 .. s.len - 1], t[0 .. t.len - 1]);

    // Else try:
    //     changing last letter of s to that of t; or
    //     remove last letter of s; or
    //     remove last letter of t,
    // any of which is 1 edit plus editing the rest of the strings
    const a = levenshtein(s[0 .. s.len - 1], t[0 .. t.len - 1]);
    const b = levenshtein(s, t[0 .. t.len - 1]);
    const c = levenshtein(s[0 .. s.len - 1], t);

    return @min(a, b, c) + 1;
}

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

    const s1 = "rosettacode";
    const s2 = "raisethysword";
    try stdout_w.print("distance between '{s}' and '{s}': {d}\n", .{ s1, s2, levenshtein(s1, s2) });
    return;
}