From ec6f6c5870014eca466c189e4cdd0d6ba040701d Mon Sep 17 00:00:00 2001 From: Dizzyi Date: Mon, 25 Mar 2024 01:11:33 +0800 Subject: [PATCH] added exercise/106_files.zig --- .gitignore | 1 + exercises/106_files.zig | 93 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 94 insertions(+) create mode 100644 exercises/106_files.zig diff --git a/.gitignore b/.gitignore index 4dc8b36..f07c7a1 100644 --- a/.gitignore +++ b/.gitignore @@ -2,3 +2,4 @@ /zig-out/ /answers/ /patches/healed/ +/output/ diff --git a/exercises/106_files.zig b/exercises/106_files.zig new file mode 100644 index 0000000..450ff96 --- /dev/null +++ b/exercises/106_files.zig @@ -0,0 +1,93 @@ +// +// Until now, we've only been printing our output in the console, +// which is good enough for fighting alien and hermit bookkeeping. +// +// However, many other task require some interaction with the file system, +// which is the underlying structure for organizing files on your computer. +// +// The File System provide a hierarchical structure for storing files +// by organizing files into directories, which hold files and other directories, +// thus creating a tree structure for navigating. +// +// Fortunately, zig standard library provide a simple api for interacting +// with the file system, see the detail documentation here +// +// https://ziglang.org/documentation/master/std/#std.fs +// +// In this exercise, we'll try to +// - create a new directory +// - open a file in the directory +// - write to the file. +// +// import std as always +const std = @import("std"); + +pub fn main() !void { + // first we get the current working directory + const cwd: std.fs.Dir = std.fs.cwd(); + + // then we'll try to make a new directory /output/ + // to put our output files. + cwd.makeDir("output") catch |e| switch (e) { + // there are chance you might want to run this + // program more than once and the path might already + // been created, so we'll have to handle this error + // by doing nothing + // + // we want to catch error.PathAlreadyExists and do nothing + ??? => { + ??? + }, + // if is any other unexpected error we just propagate it through + else => return e, + }; + + // then we'll try to open our freshly created directory + // wait a minute + // opening a directory might fail! + // what should we do here? + const output_dir: std.fs.Dir = cwd.openDir("output", .{}); + + // we try to open the file `zigling.txt`, + // and propagate the error up if there are any errors + const file: std.fs.File = try output_dir.createFile("zigling.txt", .{}); + // it is a good habit to close a file after you are done with + // so that other program can read it and prevent data corruption + // but here we are not yet done writing to the file + // if only there are a keyword in zig that + // allow you "defer" code execute to the end of scope... + file.close(); + + // !you are not allow to switch this two lines to before file closing line! + const byte_written = try file.write("It's zigling time!"); + std.debug.print("succefully wrote {} bytes.\n", .{byte_written}); +} +// to check if you actually write to the file, you can either, +// 1. open the file on your text editor, or +// 2. print the content of the file in the console with command +// >> cat ./output/zigling.txt +// +// +// More on Creating files +// +// notice in: +// ... try output_dir.createFile("zigling.txt", .{}); +// ^^^ +// we passed this anonymous struct to the function call +// +// this is the struct `CreateFlag` with default fields +// { +// read: bool = false, +// truncate: bool = true, +// exclusive: bool = false, +// lock: Lock = .none, +// lock_nonblocking: bool = false, +// mode: Mode = default_mode +// } +// +// Question: +// - what should you do if you want to also read the file after opening it? +// - go to documentation of the struct `std.fs.Dir` here +// https://ziglang.org/documentation/master/std/#std.fs.Dir +// - can you find a function for opening a file? how about deleting a file? +// - what kind of option can you uses with those function?