added shell sort (#61)

* add binary search in js

* added merge sort in c

* added quick sort in cpp

* modified quick sort

* added heap sort

* updated readme.md

* added counting sort

* added bucket sort

* added shell sort

sorting/README.md

@@ -10,6 +10,8 @@
 6. [Heap Sort](c-or-cpp/heap-sort.cpp)
 7. [Counting Sort](c-or-cpp/counting-sort.cpp)
 8. [Bucket Sort](c-or-cpp/bucket-sort.cpp)
+9. [Shell Sort](c-or-cpp/shell-sort.cpp)
+
 
 
 ### C#

sorting/c-or-cpp/shell-sort.cpp

@@ -0,0 +1,52 @@
+#include <iostream> 
+using namespace std; 
+void shellSort(int a[], int n);
+
+// Driver Code
+int main() 
+{ 
+	cout<<"Enter the length of array"<<endl;
+	int n;
+	cin>>n;
+	int *a = new int(n);
+	// Getting elements of array
+	cout<<"Enter the elements of array"<<endl;
+	for (int i = 0; i < n; i++)
+		cin>>a[i];
+    cout << "Original array: \n";
+    for (int i = 0; i < n; i++)
+        cout << a[i] << " ";
+    shellSort(a,n);
+    cout << "\nSorted array: \n";
+    for (int i = 0; i < n; i++)
+        cout << a[i] << " ";
+    delete (a);
+    return 0;
+} 
+
+void shellSort(int a[], int n) 
+{ 
+	// Starting with a big gap, then reducing the gap 
+	for (int gap = n/2; gap > 0; gap /= 2) 
+	{ 
+		// insertion sort for this gap size. 
+		for (int i = gap; i < n; i += 1) 
+		{ 
+			// add a[i] to the elements that have been gap sorted 
+			// save a[i] in temp and make a hole at position i 
+			int temp = a[i]; 
+            
+			// shift earlier gap-sorted elements up until the correct 
+			// location for a[i] is found 
+			int j;			 
+			for (j = i; j >= gap && a[j - gap] > temp; j -= gap) 
+				a[j] = a[j - gap]; 
+			
+			// put temp (the original a[i]) in its correct location 
+			a[j] = temp; 
+		} 
+	} 
+} 
+
+
+