状态机 判断实数

#include <stdio.h>
// 状态机
int isRealNumber(char *p)
{
	int state=1;
	int resualt=-1;
	while (*p)
	{
		switch(state)
		{
		case 1:
			if ('+'==*p||'-'==*p)
			{
				state=2;
			}
			else if (*p>='0'&&*p<='9')
			{
				state=4;
			}
			else if ('.'==*p)
			{
				state=3;
			}
			else
			{
				state=0;
			}
			break;
		case 2:
			if (*p>='0'&&*p<='9')
			{
				state=4;
			}
			else if ('.'==*p)
			{
				state=3;
			}
			else
			{
				state=0;
			}
			break;
		case 3:
			if (*p>='0'&&*p<='9')
			{
				state=5;
			}
			else
			{
				state=0;
			}
		    break;
		case 4:
			if (*p>='0'&&*p<='9')
			{
				state=4;
			}
			else if ('.'==*p)
			{
				state=5;
			}
			else
			{
				state=0;
			}
		    break;
		case 5:
			if (*p>='0'&&*p<='9')
			{
				state=5;
			}
			else
			{
				state=0;
			}
		    break;
		}
		if ('0'==state)
		{
			return -1;
		}
		p++;
	}
	if (4==state||5==state)
	{
		resualt=0;
	}
	return resualt;
}
int main()
{

	char str[255] = "..11111111111119";

	printf("\n%d\n",isRealNumber(str));
	return 0;
}