added exercise/106_files.zig

pull/66/head
Dizzyi 4 months ago
parent 95cfeaa606
commit ec6f6c5870

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.gitignore vendored

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/zig-out/
/answers/
/patches/healed/
/output/

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//
// 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?
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