106 & 107

This commit is contained in:
Alan CHUNG 2024-03-27 16:40:24 +08:00
parent 69bc9a0723
commit 223fc79e44
5 changed files with 100 additions and 20 deletions

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@ -1123,7 +1123,14 @@ const exercises = [_]Exercise{
}, },
.{ .{
.main_file = "106_files.zig", .main_file = "106_files.zig",
.output = "Succefully wrote 18 bytes.", .output = "Successfully wrote 18 bytes.",
},
.{
.main_file = "107_files2.zig",
.output =
\\AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
\\Successfully Read 18 byte: It's zigling time!
,
}, },
.{ .{
.main_file = "999_the_end.zig", .main_file = "999_the_end.zig",

View file

@ -35,9 +35,7 @@ pub fn main() !void {
// by doing nothing // by doing nothing
// //
// we want to catch error.PathAlreadyExists and do nothing // we want to catch error.PathAlreadyExists and do nothing
??? => { ??? => {},
???;
},
// if is any other unexpected error we just propagate it through // if is any other unexpected error we just propagate it through
else => return e, else => return e,
}; };
@ -46,7 +44,8 @@ pub fn main() !void {
// wait a minute // wait a minute
// opening a directory might fail! // opening a directory might fail!
// what should we do here? // what should we do here?
const output_dir: std.fs.Dir = cwd.openDir("output", .{}); var output_dir: std.fs.Dir = cwd.openDir("output", .{});
defer output_dir.close();
// we try to open the file `zigling.txt`, // we try to open the file `zigling.txt`,
// and propagate the error up if there are any errors // and propagate the error up if there are any errors
@ -60,7 +59,7 @@ pub fn main() !void {
// !you are not allow to switch this two lines to before file closing line! // !you are not allow to switch this two lines to before file closing line!
const byte_written = try file.write("It's zigling time!"); const byte_written = try file.write("It's zigling time!");
std.debug.print("Succefully wrote {} bytes.\n", .{byte_written}); std.debug.print("Successfully wrote {} bytes.\n", .{byte_written});
} }
// to check if you actually write to the file, you can either, // to check if you actually write to the file, you can either,
// 1. open the file on your text editor, or // 1. open the file on your text editor, or

52
exercises/107_files2.zig Normal file
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@ -0,0 +1,52 @@
//
// Prerequisite :
// - exercise/106_files.zig, or
// - create a file {project_root}/output/zigling.txt
// with content `It's zigling time!`(18 byte total)
//
// Now there no point in writing to a file if we don't read from it am I right?
// let's wrote a program to read the content of the file that we just created.
//
// I am assuming you've created the appropriate files for this to work.
//
// Alright, bud, lean in close here's the game plan.
// - First, we open the {project_root}/output/ directory
// - Secondly, we open file `zigling.txt` in that directory
// - then, we initalize an array of character with all letter 'A', and print it
// - Afte that, we read the content of the file to the array
// - Finally, we print out the read content
const std = @import("std");
pub fn main() !void {
// Get the current working directory
const cwd = std.fs.cwd();
// try to open ./output assuming you did your 106_files exercise
var output_dir = try cwd.openDir("output", .{});
defer output_dir.close();
// try to open the file
const file = try output_dir.openFile("zigling.txt", .{});
defer file.close();
// initalize an array of u8 with all letter 'A'.
// we need to pick a size of the array, 64 seems like a good number.
// fix the initalization below
var content = ['A']*64;
// this should print out : `AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA`
std.debug.print("{s}\n", .{content});
// okay, seem like threat of violence is not the answer in this case
// can you go here to find a way to read the content ?
// https://ziglang.org/documentation/master/std/#std.fs.File
// hint: you might find two answer that are both vaild in this case
const byte_read = zig_read_the_file_or_i_will_fight_you(&content);
// Woah, too screamy, I know you're excited for zigling time but tone it down a bit
// Can you print only what we read from the file ?
std.debug.print("Successfully Read {} byte: {s}\n", .{
byte_read,
content, // change this line only
});
}

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@ -1,28 +1,24 @@
--- exercises/106_files.zig --- exercises/106_files.zig 2024-03-27 16:36:44.593077000 +0800
+++ answers/106_files.zig +++ answers/106_files.zig 2024-03-27 16:36:31.548155100 +0800
@@ -35,9 +35,9 @@ pub fn main() !void { @@ -35,7 +35,7 @@
// by doing nothing // by doing nothing
// //
// we want to catch error.PathAlreadyExists and do nothing // we want to catch error.PathAlreadyExists and do nothing
- ??? => { - ??? => {},
- ???; + error.PathAlreadyExists => {},
- },
+ error.PathAlreadyExists => {
+ return;
+ },
// if is any other unexpected error we just propagate it through // if is any other unexpected error we just propagate it through
else => return e, else => return e,
}; };
@@ -46,7 +46,7 @@ pub fn main() !void { @@ -44,7 +44,7 @@
// wait a minute // wait a minute
// opening a directory might fail! // opening a directory might fail!
// what should we do here? // what should we do here?
- const output_dir: std.fs.Dir = cwd.openDir("output", .{}); - var output_dir: std.fs.Dir = cwd.openDir("output", .{});
+ const output_dir: std.fs.Dir = try cwd.openDir("output", .{}); + var output_dir: std.fs.Dir = try cwd.openDir("output", .{});
defer output_dir.close();
// we try to open the file `zigling.txt`, // we try to open the file `zigling.txt`,
// and propagate the error up if there are any errors @@ -55,7 +55,7 @@
@@ -56,7 +56,7 @@ pub fn main() !void {
// but here we are not yet done writing to the file // but here we are not yet done writing to the file
// if only there are a keyword in zig that // if only there are a keyword in zig that
// allow you "defer" code execute to the end of scope... // allow you "defer" code execute to the end of scope...

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@ -0,0 +1,26 @@
--- exercises/107_files2.zig 2024-03-27 16:36:56.733062700 +0800
+++ answers/107_files2.zig 2024-03-27 16:36:52.894505100 +0800
@@ -33,7 +33,7 @@
// initalize an array of u8 with all letter 'A'.
// we need to pick a size of the array, 64 seems like a good number.
// fix the initalization below
- var content = ['A']*64;
+ var content = [_]u8{'A'} ** 64;
// this should print out : `AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA`
std.debug.print("{s}\n", .{content});
@@ -41,12 +41,12 @@
// can you go here to find a way to read the content ?
// https://ziglang.org/documentation/master/std/#std.fs.File
// hint: you might find two answer that are both vaild in this case
- const byte_read = zig_read_the_file_or_i_will_fight_you(&content);
+ const byte_read = try file.read(&content);
// Woah, too screamy, I know you're excited for zigling time but tone it down a bit
// Can you print only what we read from the file ?
std.debug.print("Successfully Read {} byte: {s}\n", .{
byte_read,
- content, // change this line only
+ content[0..byte_read], // change this line only
});
}