MergeSort implement in C

void merge(element arr[], int left, int mid, int right, element tmp[]) {
	int i = left; // left part
	int j = mid + 1; // right part
	int k = left; // tmp index

	while (i <= mid && j <= right) {
		if (arr[i].row <= arr[j].row || (arr[i].row == arr[j].row && arr[i].col < arr[j].col)) {
			tmp[k++] = arr[i++]; // if already, keep going
		}
		else {
			tmp[k++] = arr[j++]; // if not already, back is setted.
		}
	}

	while (i <= mid) tmp[k++] = arr[i++];
	while (k <= right) tmp[k++] = arr[j++];

	//tmp -> arr 복사
	for (i = left; i <= right; i++) { arr[i] = tmp[i]; }

}

void mergeSort(element arr[], int left, int right, element tmp[]) { //ascending order
	int mid = (left + right) / 2;
	if (left < right) {
		mergeSort(arr, left, mid, tmp);
		mergeSort(arr, mid + 1, right, tmp);
		merge(arr, left, mid, right, tmp);
	}
}