diff options
Diffstat (limited to 'exercises/095_for_loops.zig')
| -rw-r--r-- | exercises/095_for_loops.zig | 99 |
1 files changed, 54 insertions, 45 deletions
diff --git a/exercises/095_for_loops.zig b/exercises/095_for_loops.zig index b437946..e4c4662 100644 --- a/exercises/095_for_loops.zig +++ b/exercises/095_for_loops.zig @@ -1,47 +1,55 @@ // -// The Zig language is in rapid development and continuously improves -// the language constructs steadily. -// -// Since version 0.11, the "for-loops" widely used in other languages -// such as C, e.g. "for (int i = 0; i < 10..." can now also be formed -// similarly in Zig, which previously required a "while" construct. -// Similar in this case actually means better, just as Zig generally -// tries to make everything simple and "better". -// -// These new "for-loops" look like the following in Zig: -// -// for (0..10) |idx| { -// // In this case 'idx' takes all values from 0 to 9. -// } -// -// This is really simple and can replace the previous, somewhat bulky: -// -// var idx: usize = 0; -// while (idx < 10) : (idx += 1) { -// // Again, idx takes all values from 0 to 9. -// } -// -// This would also simplify exercise 13, for example. -// The best way to try this out is to use this exercise, which in the -// original looks like this: -// -// ... -// 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}); -// } -// ... +// 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"); -// And now with the new "for-loop". pub fn main() void { // I want to print every number between 1 and 20 that is NOT @@ -57,8 +65,9 @@ pub fn main() void { std.debug.print("\n", .{}); } - -// Is actually a little easier. The interesting thing here is that the other -// previous 'while' exercises (11,12, 14) cannot be simplified by this -// new "for-loop". Therefore it is good to be able to use both variations -// accordingly. +// +// 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'. |