feat: examples and exercises from chapter 10

Author: damianobacci

chapter-10/01_countdown.ts

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+function countdown(n: number): void {
+  for (let i = n; i >= 0; i--) {
+    console.log(i);
+  }
+  console.log("Liftoff!");
+}
+
+function countdownRecursive(n: number): void {
+    console.log(n);
+  if (n === 0) {
+    console.log("Liftoff!");
+    return;
+  }
+  countdownRecursive(n - 1);
+}

chapter-10/02_factorial.rb

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+def factorial(number)
+    if number == 1
+        return 1
+    else
+        return number * factorial(number - 1)
+    end
+end

chapter-10/03_find_directories.js

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+const fs = require('fs');
+const path = require('path');
+
+function findDirectories(directory) {
+    const entries = fs.readdirSync(directory);
+
+    for (const entry of entries) {
+        const fullPath = path.join(directory, entry);
+        if (fs.statSync(fullPath).isDirectory() && entry !== '.' && entry !== '..') {
+            console.log(fullPath);
+
+            const innerEntries = fs.readdirSync(fullPath);
+            for (const innerEntry of innerEntries) {
+                const innerPath = path.join(fullPath, innerEntry);
+                if (fs.statSync(innerPath).isDirectory() && innerEntry !== '.' && innerEntry !== '..') {
+                    console.log(innerPath);
+                }
+            }
+        }
+    }
+}
+
+function findDirectoriesRecursive(directory) {
+    const entries = fs.readdirSync(directory);
+
+    for (const entry of entries) {
+        const fullPath = path.join(directory, entry);
+        if (fs.statSync(fullPath).isDirectory() && entry !== '.' && entry !== '..') {
+            console.log(fullPath);
+            findDirectoriesRecursive(fullPath);
+        }
+    }
+}

chapter-10/03_find_directories.rb

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+def find_directories(directory) # only works for two levels deep
+    Dir.foreach(directory) do |filename|
+        if File.directory?("#{directory}/#{filename}") && filename != '.' && filename != '..'
+            puts "#{directory}/#{filename}"
+            Dir.foreach("#{directory}/#{filename}") do |inner_filename|
+                if File.directory?("#{directory}/#{filename}/#{inner_filename}") && inner_filename != '.' && inner_filename != '..'
+                    puts "#{directory}/#{filename}/#{inner_filename}"
+                end
+            end
+        end
+    end
+end
+
+def find_directories_recursive(directory) # works for any depth
+    Dir.foreach(directory) do |filename|
+        if File.directory?("#{directory}/#{filename}") && filename != '.' && filename != '..'
+            puts "#{directory}/#{filename}"
+            find_directories_recursive("#{directory}/#{filename}")
+        end
+    end
+end

chapter-10/ex3.rb

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+def sum(low, high)
+    if low == high
+        return low
+    else
+        return high + sum(low, high - 1)
+    end
+end

chapter-10/ex4.js

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+const array = [
+    1,
+    2,
+    3,
+    [4, 5, 6],
+    7,
+    [
+        8,
+        [
+            9, 10, 11,
+            [12, 13, 14]
+        ]
+    ],
+    [
+        15, 16, 17, 18, 19,
+        [
+            20, 21, 22,
+            [
+                23, 24, 25,
+                [26, 27, 29]
+            ],
+            30, 31
+        ],
+        32
+    ],
+    33
+]
+
+function printArray(arr) {
+    arr.forEach(item => {
+        if (!Array.isArray(item)) {
+            console.log(item);
+        } else {
+            printArray(item);
+        }
+    })
+}