Thread: C/C++ examples

My version of animal guessing game in C:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

struct tree_t
{
        char* item;
        struct tree_t* left;
        struct tree_t* right;
};        

void getstr(char* s, int n)
{
        char* p;
        fgets(s, n, stdin);
        for (p=s; *p; ++p)
        {
                if (*p == '\n')
                {
                        *p = '\0';
                        break;
                }
        }
}

int yes()
{
        char buff[16];
        fgets(buff, 16, stdin);
        return (tolower(buff[0]) == 'y');
}

int main()
{

        struct tree_t* tree;
        char* guess;
        char* animal;
        char* ques;

        tree = malloc(sizeof(struct tree_t));
        tree->item = "bird";
        tree->left = tree->right = 0;

        while (1)
        {
                printf("Are you thinking of an animal? ");
                if (! yes()) break;
        
                while(tree->left)
                {
                        printf("&#37;s? ", tree->item);
                        if (yes())
                                tree = tree->right;
                        else
                                tree = tree->left;
                }
        
                guess = tree->item;
                printf("Is it %s? ", guess);
                if (yes())
                {
                        printf("I rule!\n");
                        continue;
                }
        
                printf("What is the animal's name? ");
                animal = malloc(64);
                getstr(animal, 64);
                printf("What question would distinguish a %s from a %s? ", animal, guess);
                ques = malloc(256);
                getstr(ques, 256);
                        
                tree->item = ques;
                printf("If the animal were %s the answer would be? ", animal);
                tree->left = malloc(sizeof(struct tree_t));
                tree->right = malloc(sizeof(struct tree_t));
                if (yes())
                {
                        tree->left->item = guess;
                        tree->right->item = animal;
                }
                else
                {
                        tree->left->item = animal;
                        tree->right->item = guess;
                }
                tree->left->left = tree->left->right = 0;
                tree->right->left = tree->right->right = 0;
        }
        return 0;
}

> #include <malloc.h>
Use stdlib.h for prototyping malloc

> return ((buff[0] | 32) == 'y');
toupper() or tolower() would be a lot easier to understand, and not limited to systems using ASCII.

Your main() has no return statement.