summaryrefslogtreecommitdiffstatshomepage
path: root/exercises/099_formatting.zig
diff options
context:
space:
mode:
Diffstat (limited to 'exercises/099_formatting.zig')
-rw-r--r--exercises/099_formatting.zig115
1 files changed, 115 insertions, 0 deletions
diff --git a/exercises/099_formatting.zig b/exercises/099_formatting.zig
new file mode 100644
index 0000000..788584f
--- /dev/null
+++ b/exercises/099_formatting.zig
@@ -0,0 +1,115 @@
+//
+// The output on the console looks a bit rudimentary at first glance.
+// However, if you look at the development of modern computers, you can
+// see the enormous progress that has been made over the years.
+// Starting with monochrome lines on flickering CRT monitors, modern
+// terminal emulators offer a razor-sharp image with true color and
+// nearly infinite font size thanks to modern hardware.
+//
+// In addition, they have mastered ligatures and can represent almost
+// any character in any language. This also makes the output of programs
+// on the console more atractive than ever in recent years.
+//
+// This makes it all the more important to format the presentation of
+// results in an appealing way, because that is what users appreciate,
+// quick visual comprehension of the information.
+//
+// C has set standards here over the years, and Zig is preparing to
+// follow suit. Currently, however, it still lags a bit behind the model,
+// but the Zig community is working diligently behind the scenes on
+// further options.
+//
+// Nevertheless, it is time to take a closer look at the possibilities
+// that already exist. And of course we will continue this series loosely,
+// because Zig continues to grow almost daily.
+//
+// Since there is no proper documentation on the formatting yet, the most
+// important source here is the source code:
+//
+// https://github.com/ziglang/zig/blob/master/lib/std/fmt.zig#L29
+//
+//
+// And in fact, you already discover quite a lot of useful formatting.
+// These can be used in different ways, e.g. to convert numerical values
+// into text and for direct output to the console or to a file. The latter
+// is useful when large amounts of data are to be processed by other programs.
+//
+// However, we are concerned here exclusively with the output to the console.
+// But since the formatting instructions for files are the same, what you
+// learn applies universally.
+//
+// Since we basically write to debug output in Ziglings, our output usually
+// looks like this:
+//
+// std.debug.print("Text {placeholder} another text \n", .{variable});
+//
+// But how is the statement just shown formatted?
+//
+// This actually happens in several stages. On the one hand, escape
+// sequences are evaluated, there is the "\n" which means "line feed"
+// in the example. Whenever this statement is found, a new line is started
+// in the output. Escpape sequences can also be written one after the
+// other, e.g. "\n\n" will cause two line feeds.
+//
+// By the way, these formattings are passed directly to the terminal
+// program, i.e. escape sequences have nothing to do with Zig in this
+// respect. The formatting that Zig actually performs is found in the
+// curly bracket, the "placeholder", and affects the coresponding variable.
+//
+// And this is where it gets exciting, because numbers can have different
+// sizes, be positive or negative, with a decimal point or without,
+// and so on.
+//
+// In order to bring these then into a uniform format for the output,
+// instructions can be given to the placeholder:
+//
+// print("=> {x:0>4}", .{var});
+//
+// This instruction outputs a hexadecimal number with leading zeros.
+//
+// => 0x0017
+//
+// Let's move on to our exercise: we want to create a table that shows us
+// the multiplication of all numbers together from 1-15. So if you search
+// for the number '5' in the row and '4' in the column (or vice versa),
+// the result of '5 x 4 = 20' should be displayed there.
+//
+//
+const std = @import("std");
+const print = std.debug.print;
+
+pub fn main() !void {
+ // the max. size of the table
+ const size = 15;
+
+ // print the header:
+ //
+ // we start with a single 'X' for the diagonal,
+ // that means there is no result
+ print("\n X |", .{});
+
+ // header row with all numbers from 1 to size
+ for (0..size) |n| {
+ print("{d:>3} ", .{n + 1});
+ }
+ print("\n", .{});
+
+ // row line
+ var n: u8 = 0;
+ while (n <= size) : (n += 1) {
+ print("---+", .{});
+ }
+ print("\n", .{});
+
+ // now the actual table
+ for (0..size) |a| {
+ print("{d:>2} |", .{a + 1});
+ for (0..size) |b| {
+ // what formatting is needed here?
+ print("{???} ", .{(a + 1) * (b + 1)});
+ }
+
+ // after each row we use double line feed
+ print("\n\n", .{});
+ }
+}