fix CPPLINT in sorting folder

sorting/cocktail_selection_sort.cpp

@@ -0,0 +1,101 @@
+// Returns Sorted elements after performing Cocktail Selection Sort
+// It is a Sorting algorithm which chooses the minimum and maximum element in an
+// array simultaneously, and swaps it with the lowest and highest available
+// position iteratively or recursively
+
+#include <algorithm>
+#include <iostream>
+#include <vector>
+
+// Iterative Version
+
+void CocktailSelectionSort(std::vector<int> &vec, int low, int high) {
+    while (low <= high) {
+        int minimum = vec[low];
+        int minimumindex = low;
+        int maximum = vec[high];
+        int maximumindex = high;
+
+        for (int i = low; i <= high; i++) {
+            if (vec[i] >= maximum) {
+                maximum = vec[i];
+                maximumindex = i;
+            }
+            if (vec[i] <= minimum) {
+                minimum = vec[i];
+                minimumindex = i;
+            }
+        }
+        if (low != maximumindex || high != minimumindex) {
+            std::swap(vec[low], vec[minimumindex]);
+            std::swap(vec[high], vec[maximumindex]);
+        } else {
+            std::swap(vec[low], vec[high]);
+        }
+
+        low++;
+        high--;
+    }
+}
+
+// Recursive Version
+
+void CocktailSelectionSort_v2(std::vector<int> &vec, int low, int high) {
+    if (low >= high) return;
+
+    int minimum = vec[low];
+    int minimumindex = low;
+    int maximum = vec[high];
+    int maximumindex = high;
+
+    for (int i = low; i <= high; i++) {
+        if (vec[i] >= maximum) {
+            maximum = vec[i];
+            maximumindex = i;
+        }
+        if (vec[i] <= minimum) {
+            minimum = vec[i];
+            minimumindex = i;
+        }
+    }
+    if (low != maximumindex || high != minimumindex) {
+        std::swap(vec[low], vec[minimumindex]);
+        std::swap(vec[high], vec[maximumindex]);
+    } else {
+        std::swap(vec[low], vec[high]);
+    }
+
+    CocktailSelectionSort(vec, low + 1, high - 1);
+}
+
+// main function, select any one of iterative or recursive version
+
+int main() {
+    int n;
+    std::cout << "Enter number of elements\n";
+    std::cin >> n;
+    std::vector<int> v(n);
+    std::cout << "Enter all the elements\n";
+    for (int i = 0; i < n; ++i) {
+        std::cin >> v[i];
+    }
+
+    int method;
+    std::cout << "Enter method: \n\t0: iterative\n\t1: recursive:\t";
+    std::cin >> method;
+
+    if (method == 0) {
+        CocktailSelectionSort(v, 0, n - 1);
+    } else if (method == 1) {
+        CocktailSelectionSort_v2(v, 0, n - 1);
+    } else {
+        std::cerr << "Unknown method" << std::endl;
+        return -1;
+    }
+    std::cout << "Sorted elements are\n";
+    for (int i = 0; i < n; ++i) {
+        std::cout << v[i] << " ";
+    }
+
+    return 0;
+}