added sorting algos to namespace sorting

sorting/non_recursive_merge_sort.cpp

@@ -8,13 +8,14 @@
 #include <iostream>
 #include <utility>  // for std::move & std::remove_reference_t
 
+namespace sorting {
     template <class Iterator>
     void merge(Iterator, Iterator, const Iterator, char[]);
     /// bottom-up merge sort which sorts elements in a non-decreasing order
     /**
- * sorts elements non-recursively by breaking them into small segments, merging
- * adjacent segments into larger sorted segments, then increasing the sizes of
- * segments by factors of 2 and repeating the same process.
+     * sorts elements non-recursively by breaking them into small segments,
+     * merging adjacent segments into larger sorted segments, then increasing
+     * the sizes of segments by factors of 2 and repeating the same process.
      * best-case = worst-case = O(n log(n))
      * @param first points to the first element
      * @param last points to 1-step past the last element
@@ -26,9 +27,9 @@ void non_recursive_merge_sort(const Iterator first, const Iterator last,
         // create a buffer large enough to store all elements
         // dynamically allocated to comply with cpplint
         char* buffer = new char[n * sizeof(*first)];
-    // buffer size can be optimized to largest power of 2 less than n elements
-    // divide the container into equally-sized segments whose length start at 1
-    // and keeps increasing by factors of 2
+        // buffer size can be optimized to largest power of 2 less than n
+        // elements divide the container into equally-sized segments whose
+        // length start at 1 and keeps increasing by factors of 2
         for (size_t length(1); length < n; length <<= 1) {
             // merge adjacent segments whose number is n / (length * 2)
             Iterator left(first);
@@ -55,7 +56,8 @@ void non_recursive_merge_sort(const Iterator first, const Iterator last,
     template <class Iterator>
     void merge(Iterator l, Iterator r, const Iterator e, char b[]) {
         // create 2 pointers to point at the buffer
-    auto p(reinterpret_cast<std::remove_reference_t<decltype(*l)>*>(b)), c(p);
+        auto p(reinterpret_cast<std::remove_reference_t<decltype(*l)>*>(b)),
+            c(p);
         // move the left part of the segment
         for (Iterator t(l); r != t; ++t) *p++ = std::move(*t);
         // while neither the buffer nor the right part has been exhausted
@@ -86,6 +88,10 @@ void non_recursive_merge_sort(const Iterator first, const Iterator last) {
         non_recursive_merge_sort(first, last, last - first);
     }
 
+}  // namespace sorting
+
+using sorting::non_recursive_merge_sort;
+
 int main(int argc, char** argv) {
     int size;
     std::cout << "Enter the number of elements : ";

sorting/quick_sort.cpp

@@ -24,6 +24,7 @@
 #include <cstdlib>
 #include <iostream>
 
+namespace sorting {
     /**
      *      This function takes last element as pivot, places
      *      the pivot element at its correct position in sorted
@@ -67,6 +68,10 @@ void quickSort(int arr[], int low, int high) {
         }
     }
 
+}  // namespace sorting
+
+using sorting::quickSort;
+
 // prints the array after sorting
 void show(int arr[], int size) {
     for (int i = 0; i < size; i++) std::cout << arr[i] << " ";