Merge pull request Astrodevil#367 from arihantj13/arihant

Added Shell Sort

Author: Astrodevil

DSA/DSA-CPP/Sorting Algo/ShellSort.cpp

@@ -0,0 +1,63 @@
+// C++ implementation of Shell Sort
+#include  <iostream>
+using namespace std;
+ 
+// Function to sort array using shellSort 
+int shellSort(int arr[], int n)
+{
+    // Start with a big gap, then reduce the gap
+    for (int gap = n/2; gap > 0; gap /= 2)
+    {
+        /* Do a gapped insertion sort for this gap size.
+        The first gap elements a[0..gap-1] are already in gapped order
+        keep adding one more element until the entire array is
+        gap sorted */ 
+        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 = arr[i];
+ 
+            /*shift earlier gap-sorted elements up until the correct
+            location for a[i] is found*/
+            int j;           
+            for (j = i; j >= gap && arr[j - gap] > temp; j -= gap)
+                arr[j] = arr[j - gap];
+             
+            //  put temp (the original a[i]) in its correct location
+            arr[j] = temp;
+        }
+    }
+    return 0;
+}
+ 
+void printArray(int arr[], int n)
+{
+    for (int i=0; i<n; i++)
+        cout << arr[i] << " ";
+    cout<<endl;
+}
+ 
+int main()
+{
+    int n;
+    cout<<"Enter number of elements in array\n";
+    cin>>n;
+
+    int arr[n], i;
+    cout<<"Enter elements of array\n";
+    for(i=0;i<n;i++)
+    {
+      cin>>arr[i];
+    }
+ 
+    cout << "Array before sorting: \n";
+    printArray(arr, n);
+ 
+    shellSort(arr, n);
+ 
+    cout << "Array after sorting: \n";
+    printArray(arr, n);
+ 
+    return 0;
+}