Merge pull request larissalages#172 from saiharsha-22/master

Added Sorting algorithms in C++

Author: larissalages

classical_algorithms/c++/SHELLSOR.CPP

@@ -0,0 +1,69 @@
+
+// Shell sort algorithm time complexity is best case O(nlogn) and worst case O(n^2)
+
+#include<iostream>
+using namespace std;
+class shellsort
+{
+private:
+  int a[20], n, i, j, gap, temp;
+public:
+  void getdata ()
+  {
+    cout << "enter number of elemnts:\n";
+    cin >> n;
+    cout << "enter the elements:\n";
+    for (i = 0; i < n; i++)
+      {
+	cin >> a[i];
+      }
+  }
+  void shellsorting ()
+  {
+
+    for (gap = n / 2; gap > 0; gap = gap / 2)
+      {
+	for (j = gap; j < n; j++)
+	  {
+	    for (i = j - gap; i >= 0; i -= gap)
+	      {
+		if (a[i + gap] > a[i])
+		  {
+		    break;
+		  }
+		else
+		  {
+		    swap ();
+		  }
+	      }
+	  }
+      }
+  }
+  void swap ()
+  {
+    temp = a[i + gap];
+    a[i + gap] = a[i];
+    a[i] = temp;
+
+  }
+  void display ()
+  {
+    for (i = 0; i < n; i++)
+      {
+	cout << a[i] << "\t";
+      }
+  }
+};
+
+int main ()
+{
+
+  shellsort obj;
+  obj.getdata ();
+  cout << "before sorting:";
+  obj.display ();
+  obj.shellsorting ();
+  cout << endl << "after sorting:";
+  obj.display ();
+  return 0;
+}