1. Consider the following sample code which implements the Bubble Sort. 
    void bubble_sort(int A[], int n) {
    int temp;
    for (int i=0; i<n; i++)
        for (int j=0; j<n-1; j++)
            if (A[j] > A[j+1]) {
                temp = A[j];
                A[j] = A[j+1];
                A[j+1] = temp;
            }
}

int main()
{
    int A[N];
    read_integers(A, N);
    print_integers(A, N);
    bubble_sort(A, N);
    print_integers(A, N);
    return 0;
}
  2. Modify it so that it can handle the sorting of rational numbers. 
    struct Rational {
    int numerator;      // 分子
    int denominator;    // 分母
};
  3. Your main function may look like: 
    int main()
{
    Rational A[N] = { {10, 9}, {8, 7}, {6, 5}, {4, 3}, {2, 1},
                      {1, 2}, {3, 4}, {5, 6}, {7, 8}, {9, 10} };

    print_rationals(A, N);

    bubble_sort(A, N);
    print_rationals(A, N);

    return 0;
}