From e0259f43a726f61da14686de802021fcdb9aacd0 Mon Sep 17 00:00:00 2001 From: Chris Boesch Date: Fri, 3 Apr 2026 13:35:56 +0200 Subject: Insert space for additional async exercises --- exercises/098_bit_manipulation2.zig | 64 ------------------------------------- 1 file changed, 64 deletions(-) delete mode 100644 exercises/098_bit_manipulation2.zig (limited to 'exercises/098_bit_manipulation2.zig') diff --git a/exercises/098_bit_manipulation2.zig b/exercises/098_bit_manipulation2.zig deleted file mode 100644 index 8b51265..0000000 --- a/exercises/098_bit_manipulation2.zig +++ /dev/null @@ -1,64 +0,0 @@ -// -// Another useful application for bit manipulation is setting bits as flags. -// This is especially useful when processing lists of something and storing -// the states of the entries, e.g. a list of numbers and for each prime -// number a flag is set. -// -// As an example, let's take the Pangram exercise from Exercism: -// https://exercism.org/tracks/zig/exercises/pangram -// -// A pangram is a sentence using every letter of the alphabet at least once. -// It is case insensitive, so it doesn't matter if a letter is lower-case -// or upper-case. The best known English pangram is: -// -// "The quick brown fox jumps over the lazy dog." -// -// There are several ways to select the letters that appear in the pangram -// (and it doesn't matter if they appear once or several times). -// -// For example, you could take an array of bool and set the value to 'true' -// for each letter in the order of the alphabet (a=0; b=1; etc.) found in -// the sentence. However, this is neither memory efficient nor particularly -// fast. Instead we choose a simpler approach that is very similar in principle: -// We define a variable with at least 26 bits (e.g. u32) and set the bit for -// each letter that is found in the corresponding position. -// -// Zig provides functions for this in the standard library, but we prefer to -// solve it without these extras, after all we want to learn something. -// -const std = @import("std"); -const ascii = std.ascii; -const print = std.debug.print; - -pub fn main() !void { - // let's check the pangram - print("Is this a pangram? {}!\n", .{isPangram("The quick brown fox jumps over the lazy dog.")}); -} - -fn isPangram(str: []const u8) bool { - // first we check if the string has at least 26 characters - if (str.len < 26) return false; - - // we use a 32 bit variable of which we need 26 bits - var bits: u32 = 0; - - // loop about all characters in the string - for (str) |c| { - // if the character is an alphabetical character - if (ascii.isAscii(c) and ascii.isAlphabetic(c)) { - // then we set the bit at the position - // - // to do this, we use a little trick: - // since the letters in the ASCII table start at 65 - // and are numbered sequentially, we simply subtract the - // first letter (in this case the 'a') from the character - // found, and thus get the position of the desired bit - bits |= @as(u32, 1) << @truncate(ascii.toLower(c) - 'a'); - } - } - // last we return the comparison if all 26 bits are set, - // and if so, we know the given string is a pangram - // - // but what do we have to compare? - return bits == 0x..???; -} -- cgit v1.2.3