From 1be1d854a8f690c25a577bef1feb1e9926caf2c7 Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Tue, 28 Feb 2023 20:54:42 -0500
Subject: [PATCH 1/7] first draft of memory allocation exercise
---
build.zig | 4 ++
exercises/076a_memory_allocation.zig | 70 ++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)
create mode 100644 exercises/076a_memory_allocation.zig
diff --git a/build.zig b/build.zig
index 36668b4..4617515 100644
--- a/build.zig
+++ b/build.zig
@@ -392,6 +392,10 @@ const exercises = [_]Exercise{
.main_file = "076_sentinels.zig",
.output = "Array:123056. Many-item pointer:123.",
},
+ .{
+ .main_file = "076a_memory_allocation.zig",
+ .output = "Running Average: 0.30 0.25 0.20 0.18 0.22",
+ },
.{
.main_file = "077_sentinels2.zig",
.output = "Weird Data!",
diff --git a/exercises/076a_memory_allocation.zig b/exercises/076a_memory_allocation.zig
new file mode 100644
index 0000000..b098773
--- /dev/null
+++ b/exercises/076a_memory_allocation.zig
@@ -0,0 +1,70 @@
+// 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:
+// - 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.
+//
+// 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
+// pub fn main() !void {
+//
+// var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+// defer arena.deinit();
+//
+// const allocator = arena.allocator();
+//
+// const ptr = try allocator.create(i32);
+// std.debug.print("ptr={*}\n", .{ptr});
+//
+// const slice_ptr = try allocator.create(i32);
+// 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
+
+// Given a series of numbers, take the running average. In other words, the running average of the last N elements
+
+const std = @import("std");
+
+fn runningAverage(arr: []const f64, avg: [] f64) void {
+ var sum: f64 = 0;
+
+ for (0.., arr) |index, val| {
+ sum += val;
+ avg[index] = sum / @intToFloat(f64, index + 1);
+ }
+}
+
+pub fn main() !void {
+ // pretend this was defined by reading in user input
+ var arr: []const f64 = &[_]f64{ 0.3, 0.2, 0.1, 0.1, 0.4 };
+
+ // initialize the allocator
+ var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+
+ // free the memory on exit
+ defer arena.deinit();
+
+ // initialize the allocator (TODO: replace this with ???)
+ const allocator = arena.allocator();
+
+ // TODO: replace this whole line with ???
+ var avg = try allocator.alloc(f64, arr.len);
+
+ runningAverage(arr, avg);
+ std.debug.print("Running Average: ", .{});
+ for (avg) |val| {
+ std.debug.print("{d:.2} ", .{val});
+ }
+}
+
+// For more details on memory allocation and the different types of memory allocators, see https://www.youtube.com/watch?v=vHWiDx_l4V0
From f01d9ba92d8362557aa0e4885d48de5e7975f67d Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 12:50:10 -0500
Subject: [PATCH 2/7] rephrase/reformat comments
---
exercises/076a_memory_allocation.zig | 43 ++++++++++++++++------------
1 file 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
From f08af9b24280090c599e30a3ee90b4fbfbcb3aaf Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 12:51:07 -0500
Subject: [PATCH 3/7] move memory allocation example to 095
---
build.zig | 8 ++++----
...6a_memory_allocation.zig => 095_memory_allocation.zig} | 0
2 files changed, 4 insertions(+), 4 deletions(-)
rename exercises/{076a_memory_allocation.zig => 095_memory_allocation.zig} (100%)
diff --git a/build.zig b/build.zig
index 4617515..4f9f046 100644
--- a/build.zig
+++ b/build.zig
@@ -392,10 +392,6 @@ const exercises = [_]Exercise{
.main_file = "076_sentinels.zig",
.output = "Array:123056. Many-item pointer:123.",
},
- .{
- .main_file = "076a_memory_allocation.zig",
- .output = "Running Average: 0.30 0.25 0.20 0.18 0.22",
- },
.{
.main_file = "077_sentinels2.zig",
.output = "Weird Data!",
@@ -487,6 +483,10 @@ const exercises = [_]Exercise{
.main_file = "095_for_loops.zig",
.output = "1 2 4 7 8 11 13 14 16 17 19",
},
+ .{
+ .main_file = "096_memory_allocation.zig",
+ .output = "Running Average: 0.30 0.25 0.20 0.18 0.22",
+ },
.{
.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.",
diff --git a/exercises/076a_memory_allocation.zig b/exercises/095_memory_allocation.zig
similarity index 100%
rename from exercises/076a_memory_allocation.zig
rename to exercises/095_memory_allocation.zig
From 551a36f7c92251e8e035ac9f9f878849af85a459 Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 13:09:41 -0500
Subject: [PATCH 4/7] fix allocate example
---
exercises/095_memory_allocation.zig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/exercises/095_memory_allocation.zig b/exercises/095_memory_allocation.zig
index ff54edf..057b420 100644
--- a/exercises/095_memory_allocation.zig
+++ b/exercises/095_memory_allocation.zig
@@ -25,7 +25,7 @@
// const ptr = try allocator.create(i32);
// std.debug.print("ptr={*}\n", .{ptr});
//
-// const slice_ptr = try allocator.create(f64, 5);
+// const slice_ptr = try allocator.alloc(f64, 5);
// std.debug.print("ptr={*}\n", .{ptr});
// }
From a218425ee57d0800fa685d0eb4f5040329a28da2 Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 13:21:48 -0500
Subject: [PATCH 5/7] add 095_memory_allocation.patch
---
patches/patches/095_memory_allocation.patch | 4 ++++
1 file changed, 4 insertions(+)
create mode 100644 patches/patches/095_memory_allocation.patch
diff --git a/patches/patches/095_memory_allocation.patch b/patches/patches/095_memory_allocation.patch
new file mode 100644
index 0000000..e13a27a
--- /dev/null
+++ b/patches/patches/095_memory_allocation.patch
@@ -0,0 +1,4 @@
+65c65
+< var avg: []f64 = {};
+---
+> var avg: []f64 = try allocator.alloc(f64, arr.len);
From 484822a8da1361d5878c82b0f30eafec1e3bc43e Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 13:42:21 -0500
Subject: [PATCH 6/7] rename memory allocation 095 -> 096
---
.../{095_memory_allocation.zig => 096_memory_allocation.zig} | 0
.../{095_memory_allocation.patch => 096_memory_allocation.patch} | 0
2 files changed, 0 insertions(+), 0 deletions(-)
rename exercises/{095_memory_allocation.zig => 096_memory_allocation.zig} (100%)
rename patches/patches/{095_memory_allocation.patch => 096_memory_allocation.patch} (100%)
diff --git a/exercises/095_memory_allocation.zig b/exercises/096_memory_allocation.zig
similarity index 100%
rename from exercises/095_memory_allocation.zig
rename to exercises/096_memory_allocation.zig
diff --git a/patches/patches/095_memory_allocation.patch b/patches/patches/096_memory_allocation.patch
similarity index 100%
rename from patches/patches/095_memory_allocation.patch
rename to patches/patches/096_memory_allocation.patch
From be87134397d1728b3d98d1229d241254130e0708 Mon Sep 17 00:00:00 2001
From: Sean Aubin <sean@proteinqure.com>
Date: Wed, 8 Mar 2023 19:22:17 -0500
Subject: [PATCH 7/7] change empty init to '???' placeholder
---
exercises/096_memory_allocation.zig | 4 ++--
patches/patches/096_memory_allocation.patch | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/exercises/096_memory_allocation.zig b/exercises/096_memory_allocation.zig
index 057b420..7843b93 100644
--- a/exercises/096_memory_allocation.zig
+++ b/exercises/096_memory_allocation.zig
@@ -61,8 +61,8 @@ pub fn main() !void {
// initialize the allocator
const allocator = arena.allocator();
- // allocate memory for this array instead of empty initialization
- var avg: []f64 = {};
+ // allocate memory for this array
+ var avg: []f64 = ???;
runningAverage(arr, avg);
std.debug.print("Running Average: ", .{});
diff --git a/patches/patches/096_memory_allocation.patch b/patches/patches/096_memory_allocation.patch
index e13a27a..5398ce5 100644
--- a/patches/patches/096_memory_allocation.patch
+++ b/patches/patches/096_memory_allocation.patch
@@ -1,4 +1,4 @@
65c65
-< var avg: []f64 = {};
+< var avg: []f64 = ???;
---
> var avg: []f64 = try allocator.alloc(f64, arr.len);