1 files changed, 51 insertions, 0 deletions
diff --git a/challenge-254/witawayar/cpp/ch-2.cpp b/challenge-254/witawayar/cpp/ch-2.cpp
new file mode 100644
index 0000000000..9adcfdd9e6
--- /dev/null
+++ b/challenge-254/witawayar/cpp/ch-2.cpp
@@ -0,0 +1,51 @@
+// g++ -Wall -Wextra -Wpedantic -std=c++17 cpp/ch-2.cpp
+#include <algorithm>  // copy_if, reverse, transfomr
+#include <iostream>
+#include <sstream>    // form the error message
+#include <vector>
+
+static constexpr double TOLERANCE = 1E-6;
+
+bool is_vowel(char c) { c = std::tolower(c); return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u'; }
+
+std::string fun(const std::string_view str) {
+    std::vector<char> vowels;
+    std::copy_if(str.cbegin(), str.cend(), std::back_inserter(vowels), is_vowel);
+    std::reverse(vowels.begin(), vowels.end());
+
+    std::string new_str(str.size(), '\0');
+    auto vow_it = vowels.begin();
+    std::transform(str.cbegin(), str.cend(),
+                   new_str.begin(), [&vow_it](char c) {
+                       return
+                           is_vowel(c)
+                             ? ('A' < c) && (c < 'Z')
+                               ? std::toupper(*vow_it++)
+                               : std::tolower(*vow_it++)
+                             : c;
+                   });
+
+    return new_str;
+}
+
+int main() {
+    // Tests
+    std::vector<std::pair<std::string_view, std::string_view>> tests = {
+        {"Raku", "Ruka"},
+        {"Perl", "Perl"},
+        {"Julia", "Jaliu"},
+        {"Uiua", "Auiu"},
+    };
+
+    for (const auto& [input, expected_output] : tests) {
+        auto got = fun(input);
+        if (got != expected_output) {
+            std::stringstream error_msg;
+            error_msg << "Expected " << expected_output << ", got " << got;
+            throw std::runtime_error(error_msg.str());
+        }
+    }
+
+    std::cout << "done-testing, success\n";
+
+}