// // Now that you know how "defer" works, let's do something more // interesting with it. // const std = @import("std"); pub fn main() void { const animals = [_]u8{ 'g', 'c', 'd', 'd', 'g', 'z' }; 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 // like "(Goat) ", but we somehow need to print the end parenthesis // even though this function can return in four different places! fn printAnimal(animal: u8) void { std.debug.print("(", .{}); std.debug.print(") ", .{}); // <---- how?! if (animal == 'g') { std.debug.print("Goat", .{}); return; } if (animal == 'c') { std.debug.print("Cat", .{}); return; } if (animal == 'd') { std.debug.print("Dog", .{}); return; } 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; }