chore: import upstream snapshot with attribution

math/power_of_two.cpp

@@ -0,0 +1,106 @@
+/**
+ * @file
+ * @brief Implementation to check whether a number is a power of 2 or not.
+ *
+ * @details
+ * This algorithm uses bit manipulation to check if a number is a power of 2 or
+ * not.
+ *
+ * ### Algorithm
+ * Let the input number be n, then the bitwise and between n and n-1 will let us
+ * know whether the number is power of 2 or not
+ *
+ * For Example,
+ * If N= 32 then N-1 is 31, if we perform bitwise and of these two numbers then
+ * the result will be zero, which indicates that it is the power of 2
+ * If N=23 then N-1 is 22, if we perform bitwise and of these two numbers then
+ * the result will not be zero , which indicates that it is not the power of 2
+ * \note This implementation is better than naive recursive or iterative
+ * approach.
+ *
+ * @author [Neha Hasija](https://github.com/neha-hasija17)
+ * @author [Rijul.S](https://github.com/Rijul24)
+ */
+
+#include <iostream>  /// for IO operations
+#include <cassert>   /// for assert
+
+
+/**
+ * @namespace math
+ * @brief Mathematical algorithms
+ */
+namespace math {
+/**
+ * @brief This function finds whether a number is power of 2 or not
+ * @param n value for which we want to check
+ * prints the result, as "Yes, the number n is a power of 2" or
+ * "No, the number is not a power of 2" without quotes
+ * @returns 1 if `n` IS the power of 2
+ * @returns 0 if n is NOT a power of 2
+ */
+int power_of_two(int n) {
+    /// result stores the
+    /// bitwise and of n and n-1
+    int result = n & (n - 1);
+    
+    if (result == 0) {
+        return 1;
+    }
+
+    return 0;
+}
+}  // namespace math
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void test() {
+    std::cout << "First case testing... \n"; // for n = 32 return 1
+    assert(math::power_of_two(32) == 1);
+    std::cout << "\nPassed!\n";
+
+    std::cout << "Second case testing... \n"; // for n = 5 return 0
+    assert(math::power_of_two(5) == 0);
+    std::cout << "\nPassed!\n";
+
+    std::cout << "Third case testing... \n"; // for n = 232 return 0
+    assert(math::power_of_two(232) == 0);
+    std::cout << "\nPassed!\n";
+
+    std::cout << "\nAll test cases have successfully passed!\n";
+}
+
+/**
+ * @brief Take user input in the test cases (optional; currently commented)
+ * @returns void
+ */
+void user_input_test() {
+    int n = 0; // input from user
+    
+    std::cout << "Enter a number " << std::endl;
+    std::cin >> n; 
+
+    /// function call with @param n
+    int result = math::power_of_two(n);
+    if (result == 1) {
+        std::cout << "Yes, the number " << n << " is a power of 2\n";
+    }
+    else { 
+        std::cout << "No, the number " << n << " is not a power of 2\n";
+    }
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test(); // run self-test implementations
+
+    // uncomment the line below to take user inputs
+    //user_input_test();
+
+    return 0;
+}