Merge sort

Sorting/Sorting 1

@@ -1 +1,91 @@
+// Merge sort
 
+#include<iostream>
+using namespace std;
+void swapping(int &a, int &b)
+{     //swap the content of a and b
+   int temp;
+   temp = a;
+   a = b;
+   b = temp;
+}
+void display(int *array, int size) 
+{
+   for(int i = 0; i<size; i++)
+   {
+      cout << array[i] << " ";
+   }
+   cout << endl;
+}
+void merge(int *array, int l, int m, int r) 
+{
+   int i, j, k, sl, sr;
+   //size of left and right sub-arrays
+   sl = m-l+1; sr = r-m;
+   int l_arr[sl], r_arr[sr];
+   //fill left and right sub-arrays
+   for(i = 0; i<sl; i++)
+   {
+      l_arr[i] = array[l+i];
+   }
+   for(j = 0; j<sr; j++)
+   {
+      r_arr[j] = array[m+1+j];
+   }
+   i = 0; j = 0; k = l;
+
+   //merge temp arrays to real array
+
+   while(i < sl && j<sr)
+   {
+      if(l_arr[i] <= r_arr[j])
+      {
+         array[k] = l_arr[i];
+         i++;
+      }
+      else
+      {
+         array[k] = r_arr[j];
+         j++;
+      }
+      k++;
+   }
+   while(i<sl)
+   {       //extra element in left array
+      array[k] = l_arr[i];
+      i++; k++;
+   }
+   while(j<sr)
+   {     //extra element in right array
+      array[k] = r_arr[j];
+      j++; k++;
+   }
+}
+void mergeSort(int *array, int l, int r) 
+{
+   int m;
+   if(l < r) {
+      int m = l+(r-l)/2;
+      // Sort first and second arrays
+      mergeSort(array, l, m);
+      mergeSort(array, m+1, r);
+      merge(array, l, m, r);
+   }
+}
+int main() 
+{
+   int n;
+   cout << "Enter the number of elements: ";
+   cin >> n;
+   int arr[n];     //create an array with given number of elements
+   cout << "Enter elements:" << endl;
+   for(int i = 0; i<n; i++)
+   {
+      cin >> arr[i];
+   }
+   cout << "Array before Sorting: ";
+   display(arr, n);
+   mergeSort(arr, 0, n-1);     //(n-1) for last index
+   cout << "Array after Sorting: ";
+   display(arr, n);
+}