Merge branch 'document/math' into document/temp

* document/math:
  replace printf & scanf with std::cout and std::cin
  documented factorial

math/factorial.cpp

@@ -1,14 +1,17 @@
-// C++ program to find factorial of given number
-#include<iostream>
+/**
+ * @file
+ * @brief C++ program to find factorial of given number
+ */
+#include <iostream>
 
-// function to find factorial of given number
+/** function to find factorial of given number */
 unsigned int factorial(unsigned int n) {
     if (n == 0)
         return 1;
     return n * factorial(n - 1);
 }
 
-// Driver code
+/** Main function */
 int main() {
     int num = 5;
     std::cout << "Factorial of " << num << " is " << factorial(num)

math/power_for_huge_numbers.cpp

@@ -81,10 +81,10 @@ void power(int x, int n) {
 /** Main function */
 int main() {
     int exponent, base;
-    printf("Enter base ");
-    scanf("%id \n", &base);
-    printf("Enter exponent ");
-    scanf("%id", &exponent);
+    std::cout << "Enter base ";
+    std::cin >> base;
+    std::cout << "Enter exponent ";
+    std::cin >> exponent;
     power(base, exponent);
     return 0;
 }