2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
// Help! Evil alien creatures have hidden eggs all over the Earth
|
|
|
|
// and they're starting to hatch!
|
|
|
|
//
|
2023-04-26 17:47:03 -04:00
|
|
|
// Before you jump into battle, you'll need to know three things:
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
2023-04-26 17:47:03 -04:00
|
|
|
// 1. You can attach functions to structs (and other "type definitions"):
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
// const Foo = struct{
|
|
|
|
// pub fn hello() void {
|
|
|
|
// std.debug.print("Foo says hello!\n", .{});
|
|
|
|
// }
|
2022-07-31 15:57:20 -04:00
|
|
|
// };
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
2023-04-26 17:47:03 -04:00
|
|
|
// 2. A function that is a member of a struct is "namespaced" within
|
|
|
|
// that struct and is called by specifying the "namespace" and then
|
|
|
|
// using the "dot syntax":
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
// Foo.hello();
|
|
|
|
//
|
2023-04-28 06:12:42 -04:00
|
|
|
// 3. The NEAT feature of these functions is that if their first argument
|
|
|
|
// is an instance of the struct (or a pointer to one) then we can use
|
|
|
|
// the instance as the namespace instead of the type:
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
// const Bar = struct{
|
2023-04-28 06:12:42 -04:00
|
|
|
// pub fn a(self: Bar) void {}
|
|
|
|
// pub fn b(this: *Bar, other: u8) void {}
|
|
|
|
// pub fn c(bar: *const Bar) void {}
|
2022-07-31 15:57:20 -04:00
|
|
|
// };
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
2023-04-26 17:47:03 -04:00
|
|
|
// var bar = Bar{};
|
|
|
|
// bar.a() // is equivalent to Bar.a(bar)
|
|
|
|
// bar.b(3) // is equivalent to Bar.b(&bar, 3)
|
|
|
|
// bar.c() // is equivalent to Bar.c(&bar)
|
2021-08-30 17:55:10 -04:00
|
|
|
//
|
2023-04-26 17:47:03 -04:00
|
|
|
// Notice that the name of the parameter doesn't matter. Some use
|
|
|
|
// self, others use a lowercase version of the type name, but feel
|
|
|
|
// free to use whatever is most appropriate.
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
// Okay, you're armed.
|
|
|
|
//
|
|
|
|
// Now, please zap the alien structs until they're all gone or
|
2024-05-20 15:32:32 -04:00
|
|
|
// the Earth will be doomed!
|
2021-02-27 16:52:57 -05:00
|
|
|
//
|
|
|
|
const std = @import("std");
|
|
|
|
|
|
|
|
// Look at this hideous Alien struct. Know your enemy!
|
|
|
|
const Alien = struct {
|
|
|
|
health: u8,
|
|
|
|
|
|
|
|
// We hate this method:
|
|
|
|
pub fn hatch(strength: u8) Alien {
|
|
|
|
return Alien{
|
|
|
|
.health = strength * 5,
|
|
|
|
};
|
|
|
|
}
|
2022-04-28 14:22:58 -04:00
|
|
|
};
|
|
|
|
|
|
|
|
// Your trusty weapon. Zap those aliens!
|
|
|
|
const HeatRay = struct {
|
|
|
|
damage: u8,
|
2021-02-27 16:52:57 -05:00
|
|
|
|
|
|
|
// We love this method:
|
2023-02-20 15:32:10 -05:00
|
|
|
pub fn zap(self: HeatRay, alien: *Alien) void {
|
2023-04-28 06:12:42 -04:00
|
|
|
alien.health -= if (self.damage >= alien.health) alien.health else self.damage;
|
2021-02-27 16:52:57 -05:00
|
|
|
}
|
|
|
|
};
|
|
|
|
|
|
|
|
pub fn main() void {
|
|
|
|
// Look at all of these aliens of various strengths!
|
|
|
|
var aliens = [_]Alien{
|
|
|
|
Alien.hatch(2),
|
|
|
|
Alien.hatch(1),
|
|
|
|
Alien.hatch(3),
|
|
|
|
Alien.hatch(3),
|
|
|
|
Alien.hatch(5),
|
|
|
|
Alien.hatch(3),
|
|
|
|
};
|
|
|
|
|
|
|
|
var aliens_alive = aliens.len;
|
2023-06-22 05:41:41 -04:00
|
|
|
const heat_ray = HeatRay{ .damage = 7 }; // We've been given a heat ray weapon.
|
2021-02-27 16:52:57 -05:00
|
|
|
|
|
|
|
// We'll keep checking to see if we've killed all the aliens yet.
|
|
|
|
while (aliens_alive > 0) {
|
|
|
|
aliens_alive = 0;
|
|
|
|
|
2022-07-31 12:04:56 -04:00
|
|
|
// Loop through every alien by reference (* makes a pointer capture value)
|
2023-02-21 15:43:40 -05:00
|
|
|
for (&aliens) |*alien| {
|
2021-02-27 16:52:57 -05:00
|
|
|
|
2022-07-31 11:32:51 -04:00
|
|
|
// *** Zap the alien with the heat ray here! ***
|
2022-04-28 14:22:58 -04:00
|
|
|
???.zap(???);
|
2021-02-27 16:52:57 -05:00
|
|
|
|
|
|
|
// If the alien's health is still above 0, it's still alive.
|
|
|
|
if (alien.health > 0) aliens_alive += 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
std.debug.print("{} aliens. ", .{aliens_alive});
|
|
|
|
}
|
|
|
|
|
|
|
|
std.debug.print("Earth is saved!\n", .{});
|
|
|
|
}
|