int main() {
    clock_t t;
    double tot_exec_time;
    int l = 1, u = 100000, c = 100000;
    int arr[1000000], num, i;
    srand(time(0));

    // Writing the array to a text file
    FILE *inputFile = fopen("input_array.txt", "w");
    if (inputFile == NULL) {
        printf("Error opening file for writing.\n");
        return 1;
    }
    for (i = 1; i <= c; i++) {
        num = (rand() % (u - l + 1)) + 1;
        fprintf(inputFile, "%d ", num);
    }
    fclose(inputFile);

    // Reading the array from the text file
    FILE *readFile = fopen("input_array.txt", "r");
    if (readFile == NULL) {
        printf("Error opening file for reading.\n");
        return 1;
    }
    for (i = 1; i <= c; i++) {
        fscanf(readFile, "%d", &arr[i]);
    }
    fclose(readFile);

    // Sorting the array using merge sort
    t = clock();
    mergeSort(arr, 1, c);
    t = clock() - t;
    tot_exec_time = ((double)(t) / CLOCKS_PER_SEC);

    // Writing the sorted array to a text file
    FILE *sortedFile = fopen("sorted_array.txt", "w");
    if (sortedFile == NULL) {
        printf("Error opening file for writing.\n");
        return 1;
    }
    for (i = 1; i <= c; i++) {
        fprintf(sortedFile, "%d ", arr[i]);
    }
    fclose(sortedFile);

    printf("\n");
    printf("Total time taken by Merge Sort is = %lf\n", tot_exec_time);

    return 0;