I have Wa #8 many times, I don't know what's wrong!!! Can anybody check my code or give me a hint?

There is my code, I still have WA #8:

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
int main()
{
    double x1, x2, y1, y2, Right = -1e9, Left = 1e9, Up = -1e9, Down = 1e9;

    double x3, y3, x0, y0, n, m;

    int N = 0;

    while (cin >> x1 >> y1 >> x2 >> y2)
    {
        N ++;
        x0 = (x1 + x2) / 2.0;
        y0 = (y1 + y2) / 2.0;

        n = x1 - x0;
        m = y1 - y0;
        x3 = m + x0;
        y3 = -n + y0;

        Left = min(Left, min(x1, min(x2, x3)));
        Right = max(Right, max(x1, max(x2, x3)));
        Up = max(Up, max(y1, max(y2, y3)));
        Down = min(Down, min(y1, min(y2, y3)));

    }

    if (N == 0) printf("%0.4f %0.4f", 0, 0);
    else printf("%0.4f %0.4f", fabs(Right - Left), fabs(Up - Down));

    return 0;
}

Try empty input.
If you use Java - don't use Scanner.
His hasNextDouble()/hasNextInt(), nextDouble()/nextInt() are too slow for large input.
Use StreamTokenizer.

Edited by author 31.10.2010 23:46