Merge pull request 'Add another defer exercise' (#438) from mark2185/exercises:defer3 into main

Reviewed-on: https://codeberg.org/ziglings/exercises/pulls/438

1 files changed, 23 insertions, 0 deletions

diff --git a/exercises/028_defer2.zig b/exercises/028_defer2.zig
index 35c1326..b490a89 100644
--- a/exercises/028_defer2.zig
+++ b/exercises/028_defer2.zig
@@ -10,6 +10,8 @@ pub fn main() void {
     for (animals) |a| printAnimal(a);
 
     std.debug.print("done.\n", .{});
+
+    std.debug.print("Answer to everything? {d}\n", .{calculateTheUltimateQuestionOfLife()});
 }
 
 // This function is _supposed_ to print an animal name in parentheses
@@ -35,3 +37,24 @@ fn printAnimal(animal: u8) void {
 
     std.debug.print("Unknown", .{});
 }
+
+// This function is supposed to calculate the answer to the
+// ultimate question of life, the universe, and everything,
+// but it needs to be deferred as far in the future as possible,
+// in order to gather more data.
+//
+// When there are multiple defers in a single block, they are executed in reverse order.
+// This example might seem silly, but it's important to know when e.g.
+// deinitializing containers whose elements need to be deinitialized first.
+fn calculateTheUltimateQuestionOfLife() u32 {
+    var x: u32 = 100;
+
+    // Try reordering the statements to get the answer 42
+    {
+        defer x = x / 10;
+        defer x = x + 11;
+        defer x = x * 2;
+    }
+
+    return x;
+}