#include <fstream.h>
#include <string.h>

typedef char	word[10];
enum  state {start, art1, adj1, noun1, prep1, art2, adj2, noun2, verb, padj, 
		part, pnoun, prep2, art3, adj3, noun3, done};
void searchfor (word, word[], int &);

int main ()
{
	word	list[29] = {"a", "an", "the", "huge", "polite", "green", 
						"shifty", "tired", "mean", "nice", "speckled", 
						"rough", "innocent", "dog", "horse", "Linda",
						"Donald", "elephant", "snail", "chicken", 
						"with", "on", "by", "eats", "is", "stands", 
						"calls", "feeds", "."};
	word		one;
	state		at;
	ifstream	infile;
	char		filename[30];
	int			position;
	int			stopper;
	int			num = 0;

	cout << "Enter file name: ";
	cin >> filename;
	infile.open(filename);

	infile >> one;
	while (infile)
	{
		at = start;
		stopper = 0;
		while (at != done && stopper == 0)
		{ 
			searchfor(one, list, position);  // cout << (int) at << ' ' << position << "p ";
			switch (at)
			{
			case start: 
			case prep1:
			case prep2:
						if (position < 3) 
							at = (state) (at + 1);
						else if (position < 13)
							at = (state) (at + 2);
						else if (position < 20)
							at = (state) (at + 3);
						else
							stopper = 1;
						break;
			case art1:
			case art2:
			case art3:	if (position > 2 && position < 13)
							at = (state) (at + 1);
						else if (position > 12 && position < 20)
							at = (state) (at + 2);
						else
							stopper = 1;
						break;
			case adj1:
			case adj2:
			case adj3:	if (position > 2 && position < 13)
							;
						else if (position > 12 && position < 20)
							at = (state) (at + 1);
						else 
							stopper = 1;
						break;
			case noun1: if (position > 19 && position < 23)
							at = prep1;
						else if (position > 22 && position < 28)
							at = verb;
						else
							stopper = 1;
						break;
			case noun2: if (position > 22 && position < 28)
							at = verb;
						else
							stopper = 1;
						break;
			case verb:	if (position < 3)
							at = part;
						else if (position < 13)
							at = padj;
						else if (position < 20)
							at = pnoun;
						else if (position > 19 && position < 23)
							at = prep2;
						else
							stopper = 1;
						break;
			case part:	if (position > 12 && position < 20)
							at = pnoun;
						else
							stopper = 1;
						break;
			case padj:
			case pnoun:
			case noun3:	if (position == 28)
							at = done;
						else
							stopper = 1;
			}
			if (at != done && stopper == 0)
				infile >> one;
		}
		num++;
		if (at == done)
			cout << "Sentence " << num << " is VALID\n";
		else
			cout << "Sentence " << num << " is NOT in the language\n";
		if (position != 28)
			infile.ignore(200, '.');
		infile >> one;
	}
	infile.close();
	return 0;
}

void searchfor (word  val, word  group[], int& found)
{
	for (found = 0; found < 29; found++)
		if (strcmp(val, group[found]) == 0)
			break;
}