blob: 05edd3b314c8686ff6c95e9e48c3a82fceb5ee08 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
//
// You can also make pointers to multiple items without using a slice.
//
// var foo: [4]u8 = [4]u8{ 1, 2, 3, 4 };
// var foo_slice: []u8 = foo[0..];
// var foo_ptr: [*]u8 = &foo;
//
// The difference between foo_slice and foo_ptr is that the slice has
// a known length. The pointer doesn't. It is up to YOU to keep track
// of the number of u8s foo_ptr points to!
//
const std = @import("std");
pub fn main() void {
// Take a good look at the type of the zen12 string:
const zen12: *const [21]u8 = "Memory is a resource.";
// It would also have been valid to coerce this to a slice:
//
// const zen12: []const u8 = "...";
//
// Now let's turn this into a "many pointer":
const zen_manyptr: [*]const u8 = zen12;
// It's okay to access zen_manyptr just like an array or slice as
// long as you keep track of the length yourself!
//
// A "string" in Zig is a pointer to an array of const u8 values
// or a slice of const u8 values, into one, as we saw above). So,
// we could treat a "many pointer" of const u8 a string as long
// as we can CONVERT IT TO A SLICE. (Hint: we do know the length!)
//
// Please fix this line so the print below statement can print it:
const zen12_string: []const u8 = zen_manyptr;
// Here's the moment of truth!
std.debug.print("{s}\n", .{zen12_string});
}
//
// Are all of these pointer types starting to get confusing?
//
// FREE ZIG POINTER CHEATSHEET! (Using u8 as the example type.)
// +---------------+----------------------------------------------+
// | u8 | one u8 |
// | *u8 | pointer to one u8 |
// | [2]u8 | two u8s |
// | [*]u8 | pointer to unknown number of u8s |
// | [2]const u8 | two immutable u8s |
// | [*]const u8 | pointer to unknown number of immutable u8s |
// | *[2]u8 | pointer to an array of 2 u8s |
// | *const [2]u8 | pointer to an immutable array of 2 u8s |
// | []u8 | slice of u8s |
// | []const u8 | slice of immutable u8s |
// +---------------+----------------------------------------------+
|
