ziglings/32_unreachable.zig

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//
// Zig has an "unreachable" statement. Use it when you want to tell the
// compiler that a branch of code should never be executed and that the
// mere act of reaching it is an error.
//
// if (true) {
// ...
// } else {
// unreachable;
// }
//
// Here we've made a little virtual machine that performs mathematical
// operations on a single numeric value. It looks great but there's one
// little problem: the switch statement doesn't cover every possible
// value of a u8 number!
//
// WE know there are only three operations but Zig doesn't. Use the
// unreachable statement to make the switch complete. Or ELSE. :-)
//
const std = @import("std");
pub fn main() void {
const operations = [_]u8{ 1, 1, 1, 3, 2, 2 };
var current_value: u32 = 0;
for (operations) |op| {
switch (op) {
1 => { current_value += 1; },
2 => { current_value -= 1; },
3 => { current_value *= current_value; },
}
std.debug.print("{} ", .{current_value});
}
std.debug.print("\n", .{});
}