Added Palindrome Algorithm in Cpp and updated README.md

Author: ricardocarva

README.md

@@ -3500,8 +3500,8 @@ Com o objetivo de alcançar uma abrangência maior e encorajar mais pessoas a co
                 </a>
             </td>
             <td> <!-- C++ -->
-                <a href="./CONTRIBUTING.md">
-                    <img align="center" height="25" src="https://cdn.jsdelivr.net/gh/devicons/devicon/icons/github/github-original.svg" />
+                <a href="/src/cpp/Palindrome.cpp">
+                    <img align="center" height="25" src="https://cdn.jsdelivr.net/gh/devicons/devicon/icons/cplusplus/cplusplus-original.svg" />
                 </a>
             </td>
             <td> <!-- Java -->

src/cpp/Palindrome.cpp

@@ -0,0 +1,56 @@
+/*
+isPalindrome Algorithm in C++
+Ricardo Ferreira Carvalheira - 2023
+https://github.com/ricardocarva
+
+    A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
+
+    Given a string s, return true if it is a palindrome, or false otherwise.
+*/
+#include <iostream>
+
+#include <string>
+
+using namespace std;
+
+bool isPalindrome(string s) {
+    // Step 1: Convert all characters to lowercase
+    for (char& c : s) {
+        c = std::tolower(c);
+    }
+
+    // Step 2: Remove non-alphanumeric characters
+    std::string alphanumericStr;
+    for (char c : s) {
+        if (std::isalnum(c)) {
+            alphanumericStr.push_back(c);
+        }
+    }
+
+    // Step 3: Check if the resulting string is a palindrome
+    int left = 0;
+    int right = alphanumericStr.length() - 1;
+
+    while (left < right) {
+        if (alphanumericStr[left] != alphanumericStr[right]) {
+            return false;
+        }
+        left++;
+        right--;
+    }
+    return true;
+}
+
+int main() {
+    std::string input;
+    std::cout << "Enter a string: ";
+    std::cin >> input;
+
+    if (isPalindrome(input)) {
+        std::cout << "The string is a palindrome." << std::endl;
+    }
+    else {
+        std::cout << "The string is not a palindrome." << std::endl;
+    }
+    return 0;
+}