shift zig implementation (naive ver.)

main.zig

const std = @import("std");
const fmt = std.fmt;
const mem = std.mem;
const print = std.debug.print;
const assert = std.debug.assert;
const expect = std.testing.expect;

pub var allocator: std.mem.Allocator = undefined;

pub fn main() !void {
    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    defer arena.deinit();
    allocator = arena.allocator();

    var word = [_]u8{ 'a', 'b', 'c' };
    // var word = [_]u8{ 'a', 'b', 'c', 'x', 'y', 'z' };

    print("word '{s}', len {d}\n", .{ word, word.len }); // word 'abc', len 3
    const r = shift(&word);
    print("word '{s}', len {d}\n", .{ word, word.len }); // word 'bc', len 3
    print("{c}\n", .{r}); // a
}

// slice len is not chagend...
fn shift(array: []u8) u8 {
    const r = array[0];

    var i: usize = 0;
    while (i == array.len - 1) : (i += 1) {
        array[i] = array[i + 1];
    }

    array[i] = '\x00';

    return r;
}