OJ Board

Code: Select all

#include <iostream>
using namespace std;
char str[1000];
int trans[8][4] = 
{
	{1,2,9,9},
	{9,2,9,9},
	{9,2,3,5},
	{9,4,9,9},
	{9,4,9,5},
	{6,7,9,9},
	{9,7,9,9},
	{9,7,9,9}
};
int getMap (char c) {
	switch (c)
	{
		case '+':
		case '-':
			return 0;
			break;
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
			return 1;
			break;
		case '.':
			return 2;
			break;
		case 'e':
		case 'E':
			return 3;
			break;
		default:
			return 4;
			break;
	}
}
int check ()
{
	int len = strlen(str);
	int state = 0;
	int i,j;
	char *p = str;
	for (i=len-1;i>=0;i--)
		if (str[i]!=' ')
		{
			str[i+1] = '\0';
			break;
		}
	while (*p==' ') p++;
	cout<<p;
	for (;*p;p++)
	{
		j = getMap(*p);
		state = trans[state][j];
		if (state==9) return 0;
	}
	return (state==2 || state==4 || state==7);
}
int main ()
{
	while (1)
	{
		cin.getline(str,999);
		if (str[0]=='*') break;
		if (check())
		{
			cout<<" is legal."<<endl;
		} else
		{
			cout<<" is illegal."<<endl;
		}
		
	}
	return 0;
}