diff options
Diffstat (limited to 'exercises')
| -rw-r--r-- | exercises/105_threading2.zig | 2 | ||||
| -rw-r--r-- | exercises/106_files.zig | 92 | ||||
| -rw-r--r-- | exercises/107_files2.zig | 52 |
3 files changed, 145 insertions, 1 deletions
diff --git a/exercises/105_threading2.zig b/exercises/105_threading2.zig index ac3cdfb..c85f801 100644 --- a/exercises/105_threading2.zig +++ b/exercises/105_threading2.zig @@ -1,5 +1,5 @@ // -// Now that we are familiar with the principles of multithreading, we +// Now that we are familiar with the principles of multi threading, we // boldly venture into a practical example from mathematics. // We will determine the circle number PI with sufficient accuracy. // diff --git a/exercises/106_files.zig b/exercises/106_files.zig new file mode 100644 index 0000000..aa58ee0 --- /dev/null +++ b/exercises/106_files.zig @@ -0,0 +1,92 @@ +// +// 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? + var output_dir: std.fs.Dir = cwd.openDir("output", .{}); + defer output_dir.close(); + + // 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("Successfully wrote {d} 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? diff --git a/exercises/107_files2.zig b/exercises/107_files2.zig new file mode 100644 index 0000000..dadfdf6 --- /dev/null +++ b/exercises/107_files2.zig @@ -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 {d} byte: {s}\n", .{ + byte_read, + content, // change this line only + }); +} |