Mergesort using cpp

06. Sorting/Mergesort using cpp

@@ -0,0 +1,74 @@
+#include <iostream>
+using namespace std;
+void merge(int *,int, int , int );
+void merge_sort(int *arr, int low, int high)
+{
+   int mid;
+   if (low < high){
+      //divide the array at mid and sort independently using merge sort
+      mid=(low+high)/2;
+      merge_sort(arr,low,mid);
+      merge_sort(arr,mid+1,high);
+      //merge or conquer sorted arrays
+      merge(arr,low,high,mid);
+   }
+}
+// Merge sort
+void merge(int *arr, int low, int high, int mid)
+{
+   int i, j, k, c[50];
+   i = low;
+   k = low;
+   j = mid + 1;
+   while (i <= mid && j <= high) {
+   if (arr[i] < arr[j]) {
+   c[k] = arr[i];
+   k++;
+   i++;
+}
+else {
+   c[k] = arr[j];
+   k++;
+   j++;
+   }
+}
+
+while (i <= mid) {
+   c[k] = arr[i];
+   k++;
+   i++;
+}
+while (j <= high) {
+   c[k] = arr[j];
+   k++;
+   j++;
+}
+for (i = low; i < k; i++) {
+   arr[i] = c[i];
+}
+}
+// read input array and call mergesort
+int main()
+{
+int myarray[30], num;
+cout<<"Enter number of elements to be sorted:";
+cin>>num;
+cout<<"Enter "<<num<<" elements to be sorted:";
+for (int i = 0; i < num; i++) { cin>>myarray[i];
+}
+merge_sort(myarray, 0, num-1);
+cout<<"Sorted array\n";
+for (int i = 0; i < num; i++)
+{
+   cout<<myarray[i]<<"\t";
+}
+}
+Output:
+
+Enter number of elements to be sorted:5
+
+Enter 5 elements to be sorted:10 21 47 3 59
+
+Sorted array
+
+3       10      21      47      59