打印螺旋方阵

#include <stdio.h>

#define N  5
#define max(a,b) ((a)<(b)?(b):(a))
#define abs(a)   ((a)>0?(a):(-a))

int foo(int x, int y)
{
	int t = max(abs(x),abs(y));
	int u = t + t;
	int v = u - 1;
	v = v * v + u;

	if (x == -t)
	{
		v+= u + t - y;
	}
	else if (y == -t)
	{
		v += 3*u+x-t;
	}
	else if (y == t)
	{
		v += t - x;
	}
	else
	{
		 v += y - t;
	}

	return v;
}

int main()
{
	int x, y;

	for (y=1-N; y<=N-1; y++)
	{
		for (x=1-N; x<=N-1; x++)
		{
			printf("%5d",foo(x,y));
		}
		printf("\n");
	}

	return 0;
}