Merge Sort

#include<iostream>
 
using namespace std;
 
class Node {
public:
    int key, value;
};
 
Node tmp[100];
 
void MergeSort(Node* arr, int start, int end) {
    if (start >= end)
        return;
 
    int mid = (end - start) / 2 + start;
 
    MergeSort(arr, start, mid);
    MergeSort(arr, mid + 1, end);
 
    //PartSort(arr, start, end, mid);
 
    int i = start, j = mid + 1;
    int index = start;
    while (i <= mid && j <= end) {
        if (arr[i].key < arr[j].key)
            tmp[index] = arr[i++];
        else
            tmp[index] = arr[j++];
        index++;
    }
 
    while (i <= mid)
        tmp[index++] = arr[i++];        
 
    while (j <= end)
        tmp[index++] = arr[j++];
        
    for (int k = start; k <= end; k++)
        arr[k] = tmp[k];
}
 
 
int main(void) {
    Node arr[10];
    for (int i = 0; i < 10; i++) {
        arr[i].key = 9 - i;
        arr[i].value = 9 - i;
    }
 
    MergeSort(arr, 0, 9);
 
    cout << endl;
 
    return 0;
}