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