Update modular_exponentiation.cpp

math/modular_exponentiation.cpp

@@ -1,8 +1,8 @@
 /**
  * @file
  * @brief C++ Program for Modular Exponentiation Iteratively.
- * Calculate the value of an integer a raised to an integer exponent b
- * under modulo c.
+ * Calculate the value of an integer a raised to an integer exponent b 
+ * under modulo c. 
  * @note The time complexity of this approach is O(log b).
  *
  * Example:
@@ -15,46 +15,60 @@
  * We can also verify the result as 4^3 is 64 and 64 modulo 5 is 4
  */
 
-#include <iostream>
-
-/// Iterative Function to calculate a raised to exponent b
-/// under modulo c in O(log b) using modular exponentiation.
-int power(int a, unsigned int b, int c) {
-    int ans = 1;  /// Initialize the answer to be returned
-
-    a = a % c;  /// Update a if it is more than or
-                /// equal to c
-
-    if (a == 0) {
-        return 0;  /// In case a is divisible by c;
-    }
-
-    while (b > 0) {
-        /// If b is odd, multiply a with answer
-        if (b & 1) {
-            ans = (ans * a) % c;
-        }
-
-        /// b must be even now
-        b = b >> 1;  // b = b/2
-        a = (a * a) % c;
-    }
-
-    return ans;
-}
+#include <iostream> 
 
 /**
- * @brief Main function
- * @returns 0 on exit
- */
-int main() {
-    /// Give two numbers num1, num2 and modulo m
-    int num1 = 2;
-    int num2 = 5;
-    int m = 13;
+* @brief This function calculates a raised to exponent b 
+* under modulo c using modular exponentiation.
+* @param a integer base
+* @param b unsigned integer exponent
+* @param c integer modulo
+* @return a raised to power b modulo c.
+*/
+int power(int a, unsigned int b, int c) 
+{ 
+	int ans = 1;	    	/// Initialize the answer to be returned 
+
+	a = a % c;          	/// Update a if it is more than or 
+				/// equal to c 
+
+	if (a == 0) 
+	{
+	    return 0;       	/// In case a is divisible by c; 
+	}
+	
+	while (b > 0) 
+	{ 
+		/// If b is odd, multiply a with answer 
+		if (b & 1) 
+		{
+			ans = (ans*a) % c; 
+		}
+		
+		/// b must be even now 
+		b = b>>1;       // b = b/2 
+		a = (a*a) % c; 
+	}
+	
+	return ans; 
+} 
+
+/**
+* @brief Main function
+* @returns 0 on exit
+*/
+int main() 
+{ 	
+	/// Give two numbers num1, num2 and modulo m
+	int num1 = 2; 
+	int num2 = 5; 
+	int m = 13; 
+	
+	std::cout << "The value of "<<num1<<" raised to exponent "<<num2<< 
+	" under modulo "<<m<<" is " << power(num1, num2, m); 
+	/// std::cout << "The value of "<<num1<<" raised to exponent "<<num2<<" 
+	/// " under modulo "<<m<<" is " << power(num1, num2, m); 
+
+	return 0;
+} 
 
-    std::cout << "The value of " << num1 << " raised to exponent " << num2
-              << " under modulo " << m << " is " << power(num1, num2, m);
-    /// std::cout << "The value of "<<num1<<" raised to exponent "<<num2<<"
-    /// " under modulo "<<m<<" is " << power(num1, num2, m);
-}