Merge pull request #196 from chrboesch/for-loops

exercise for new for-loops

README.md

@@ -42,7 +42,7 @@ Verify the installation and build number of `zig` like so:
 
 ```bash
 $ zig version
-0.11.0-dev.1711+xxxxxxxxx
+0.11.0-dev.1844+xxxxxxxxx
 ```
 
 Clone this repository with Git:
@@ -82,7 +82,7 @@ about input:
 
 ### Version Changes
 
-Version-0.11.0-dev.1711+xxxxxxxxx
+Version-0.11.0-dev.1844+xxxxxxxxx
 * *2023-02-21* zig 0.11.0-dev.1711 - changes in `for loops` - new: Multi-Object For-Loops + Struct-of-Arrays
 * *2023-02-12* zig 0.11.0-dev.1638 - changes in `std.Build` cache_root now returns a directory struct
 * *2023-02-04* zig 0.11.0-dev.1568 - changes in `std.Build` (combine `std.build` and `std.build.Builder` into `std.Build`)

build.zig

@@ -8,7 +8,7 @@ const print = std.debug.print;
 // When changing this version, be sure to also update README.md in two places:
 //     1) Getting Started
 //     2) Version Changes
-const needed_version = std.SemanticVersion.parse("0.11.0-dev.1711") catch unreachable;
+const needed_version = std.SemanticVersion.parse("0.11.0-dev.1844") catch unreachable;
 
 const Exercise = struct {
     /// main_file must have the format key_name.zig.
@@ -479,6 +479,10 @@ const exercises = [_]Exercise{
         .output = "The normalized angle of 765.2 degrees is 45.2 degrees.",
         .C = true,
     },
+    .{
+        .main_file = "095_for_loops.zig",
+        .output = "1 2 4 7 8 11 13 14 16 17 19",
+    },
     .{
         .main_file = "999_the_end.zig",
         .output = "\nThis is the end for now!\nWe hope you had fun and were able to learn a lot, so visit us again when the next exercises are available.",

exercises/095_for_loops.zig

@@ -0,0 +1,64 @@
+//
+// 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});
+//            }
+//            ...
+//
+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
+    // 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", .{});
+}
+
+// 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.

patches/patches/095_for_loops.patch

@@ -0,0 +1,4 @@
+49c49
+<     for (???) |n| {
+---
+>     for (1..21) |n| {