diff options
| -rw-r--r-- | exercises/076a_memory_allocation.zig | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/exercises/076a_memory_allocation.zig b/exercises/076a_memory_allocation.zig index b098773..ff54edf 100644 --- a/exercises/076a_memory_allocation.zig +++ b/exercises/076a_memory_allocation.zig @@ -1,22 +1,22 @@ -// In most of the examples so far, the inputs are known at compile time, thus -// the amount of memory used by the program is fixed and is requested. However, if responding to -// input whose size is not known at compile time, such as: +// In most of the examples so far, the inputs are known at compile +// time, thus the amount of memory used by the program is fixed. +// However, if responding to input whose size is not known at compile +// time, such as: // - user input via command-line arguments // - inputs from another program // -// You'll need to request memory for you program to be allocated by your -// operating system at runtime. +// You'll need to request memory for your program to be allocated by +// your operating system at runtime. // -// Zig provides several different allocators. In the Zig documentation, it -// recommends the Arena allocator for simple programs which allocate once and -// then exit: +// Zig provides several different allocators. In the Zig +// documentation, it recommends the Arena allocator for simple +// programs which allocate once and then exit: // // const std = @import("std"); // -// // memory allocation can fail because your computer is out of memory, so -// // the return type is !void +// // memory allocation can fail, so the return type is !void // pub fn main() !void { -// +// // var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator); // defer arena.deinit(); // @@ -25,17 +25,21 @@ // const ptr = try allocator.create(i32); // std.debug.print("ptr={*}\n", .{ptr}); // -// const slice_ptr = try allocator.create(i32); +// const slice_ptr = try allocator.create(f64, 5); // std.debug.print("ptr={*}\n", .{ptr}); // } -// Instead of a simple integer, this program requires a slice to be allocated that is the same size as an input array +// Instead of an simple integer or a constant sized slice, this +// program requires a slice to be allocated that is the same size as +// an input array. -// Given a series of numbers, take the running average. In other words, the running average of the last N elements +// Given a series of numbers, take the running average. In other +// words, each item N should contain the average of the last N +// elements. const std = @import("std"); -fn runningAverage(arr: []const f64, avg: [] f64) void { +fn runningAverage(arr: []const f64, avg: []f64) void { var sum: f64 = 0; for (0.., arr) |index, val| { @@ -54,11 +58,11 @@ pub fn main() !void { // free the memory on exit defer arena.deinit(); - // initialize the allocator (TODO: replace this with ???) + // initialize the allocator const allocator = arena.allocator(); - // TODO: replace this whole line with ??? - var avg = try allocator.alloc(f64, arr.len); + // allocate memory for this array instead of empty initialization + var avg: []f64 = {}; runningAverage(arr, avg); std.debug.print("Running Average: ", .{}); @@ -67,4 +71,5 @@ pub fn main() !void { } } -// For more details on memory allocation and the different types of memory allocators, see https://www.youtube.com/watch?v=vHWiDx_l4V0 +// For more details on memory allocation and the different types of +// memory allocators, see https://www.youtube.com/watch?v=vHWiDx_l4V0 |