..
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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73 | //
// The Zig language is in rapid development and continuously
// improves the language constructs. Ziglings evolves with it.
//
// Until version 0.11, Zig's 'for' loops did not directly
// replicate the functionality of the C-style: "for(a;b;c)"
// which are so well suited for iterating over a numeric
// sequence.
//
// Instead, 'while' loops with counters clumsily stood in their
// place:
//
// var i: usize = 0;
// while (i < 10) : (i += 1) {
// // Here variable 'i' will have each value 0 to 9.
// }
//
// But here we are in the glorious future and Zig's 'for' loops
// can now take this form:
//
// for (0..10) |i| {
// // Here variable 'i' will have each value 0 to 9.
// }
//
// The key to understanding this example is to know that '0..9'
// uses the new range syntax:
//
// 0..10 is a range from 0 to 9
// 1..4 is a range from 1 to 3
//
// At the moment, ranges are only supported in 'for' loops.
//
// Perhaps you recall Exercise 13? We were printing a numeric
// sequence like so:
//
// var n: u32 = 1;
//
// // I want to print every number between 1 and 20 that is NOT
// // divisible by 3 or 5.
// while (n <= 20) : (n += 1) {
// // The '%' symbol is the "modulo" operator and it
// // returns the remainder after division.
// if (n % 3 == 0) continue;
// if (n % 5 == 0) continue;
// std.debug.print("{} ", .{n});
// }
//
// Let's try out the new form of 'for' to re-implement that
// exercise:
//
const std = @import("std");
pub fn main() void {
// I want to print every number between 1 and 20 that is NOT
// divisible by 3 or 5.
for (???) |n| {
// The '%' symbol is the "modulo" operator and it
// returns the remainder after division.
if (n % 3 == 0) continue;
if (n % 5 == 0) continue;
std.debug.print("{} ", .{n});
}
std.debug.print("\n", .{});
}
//
// That's a bit nicer, right?
//
// Of course, both 'while' and 'for' have different advantages.
// Exercises 11, 12, and 14 would NOT be simplified by switching
// a 'while' for a 'for'.
|
|
