test: Add self-test cases in the math/power_of_two.cpp file (#1640)

* Added self implement cases power_of_two.cpp

added assert & a clean code.

* added self implementation cases

* added desciption

* update

Co-authored-by: David Leal <halfpacho@gmail.com>
Co-authored-by: Abhinn Mishra <49574460+mishraabhinn@users.noreply.github.com>

math/power_of_two.cpp

@@ -19,9 +19,12 @@
  * approach.
  *
  * @author [Neha Hasija](https://github.com/neha-hasija17)
+ * @author [Rijul.S](https://github.com/Rijul24)
  */
 
-#include <iostream>  /// for std::cout
+#include <iostream>  /// for IO operations
+#include <cassert>   /// for assert
+
 
 /**
  * @namespace math
@@ -29,38 +32,75 @@
  */
 namespace math {
 /**
- * @brief Function to test above algorithm
- * @param n description
- * @returns void
+ * @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
  */
-void power_of_two(int n) {
-    /**
-     * 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
-     */
+int power_of_two(int n) {
     /// result stores the
     /// bitwise and of n and n-1
     int result = n & (n - 1);
+    
     if (result == 0) {
-        std::cout << "Yes, the number " << n << " is a power of 2";
+        return 1;
     } else {
-        std::cout << "No, the number " << n << " is not a power of 2";
+        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() {
-    int n = 0;
-    /// n stores the input from the user
-    std::cout << "enter a number " << std::endl;
-    std::cin >> n;
-    /// function call with @param n
-    math::power_of_two(n);
+    test(); // run self-test implementations
+
+    // uncomment the line below to take user inputs
+    //user_input_test();
+
     return 0;
 }