Read file

.gitignore

@@ -0,0 +1,4 @@
+inputs
+zig-out
+zig-cache
+

inputs_test/01

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+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet
+

src/main.zig

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 const std = @import("std");
 
+const print = std.debug.print;
+
 pub fn main() !void {
     // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
     std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
 
-    // stdout is for the actual output of your application, for example if you
-    // are implementing gzip, then only the compressed bytes should be sent to
-    // stdout, not any debugging messages.
-    const stdout_file = std.io.getStdOut().writer();
-    var bw = std.io.bufferedWriter(stdout_file);
-    const stdout = bw.writer();
+    try day01part1(file_name(false, "01"));
+    try day01part1(file_name(true, "01"));
+}
 
-    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+fn day01part1(filename: []const u8) !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
 
-    try bw.flush(); // don't forget to flush!
+    const file = try std.fs.cwd().openFile(filename, .{});
+    defer file.close();
+
+    var buf_reader = std.io.bufferedReader(file.reader());
+    const reader = buf_reader.reader();
+
+    var line = std.ArrayList(u8).init(allocator);
+    defer line.deinit();
+
+    const writer = line.writer();
+    while (reader.streamUntilDelimiter(writer, '\n', null)) {
+        defer line.clearRetainingCapacity();
+
+        print(":D {s}\n", .{line.items});
+    } else |err| switch (err) {
+        error.EndOfStream => {},
+        else => return err,
+    }
+}
+
+/// Creates an input file name at comptime
+fn file_name(comptime is_test: bool, comptime day: []const u8) []const u8 {
+    const input_suffix = if (is_test) "_test/" else "/";
+    return "inputs" ++ input_suffix ++ day;
 }
 
 test "simple test" {