p4.c

/* DO NOT MODIFY THIS FILE */

#define MAXSTR 80

#include <stdio.h>
#include "animal.h"
#include <stdbool.h>

/*
 *  Play the "animal" game, in which the program attempts to guess an animal
 *  that the user is thinking of by asking yes or no questions. Eventually,
 *  the program either will guess the user's animal or run out of questions
 *  to ask. In the latter case, the program will ask the user to provide a
 *  yes-or-no question that would distinguish between the user's animal and
 *  the program's best guess.
 *  The data structure of questions and guesses is essentially a binary tree,
 *  with each internal node having a "yes" branch and a "no" branch. Leaves
 *  of the tree represent animals to be guessed by the program. If the program
 *  fails to guess the user's animal, it replaces one of the leaves of the tree
 *  by a node containing the new question, whose children are the program's
 *  best guess and the animal provided by the user.
 *  The structure of the program is simple. It initializes the question/guess
 *  data structure, then plays games as long as the user is interested. In each
 *  game, the program starts at the top of the tree (the root) and progresses
 *  toward the bottom (the leaves) depending on the user's responses. Once it
 *  reaches a leaf, it either has won or lost, and handles the situation as
 *  described above.
 */
int main (int argc, char *argv[])
{
    
    char *treefile = NULL;
    TreeType tree;
    PositionType pos;
    char *newQuestion, *newAnswer;

    if (argc > 1) {
        treefile = argv[1];
    }
    
    tree = InitTree (treefile);
    printf("%s", "Think of an animal. I will try to guess what it is.\n"
		 "Please answer my questions with yes or no.\n");
    while (true) {
        pos = Top (tree);
        while (!IsLeaf (tree, pos)) {
            pos = Answer(Question(tree,pos))? 
	       YesNode(tree,pos): NoNode(tree,pos);
        }
        if (Answer (Guess (tree, pos))) {
            printf ("I got it right!\n");
        } else {
            GetNewInfo (tree, pos, &newAnswer, &newQuestion);
            ReplaceNode (tree, pos, newAnswer, newQuestion);
        }

        if (!Answer ("Want to play again? ")) {
            WriteTree(tree, treefile);
            exit (0);
        }
    }
}