POJ-1577

#include <stdio.h>
#include <string.h>
#include <malloc.h>

typedef struct node *node_pointer;
struct node{
            char value;
            node_pointer left, right;
       };

node_pointer tree;

int dataSets(void)
{
     char data[50];
     node_pointer *temp;
     int i;
     short int b;
     scanf("%s", data);
     if (!strcmp(data, "*"))
        return 1;
     if (!strcmp(data, "$"))
        return 0;
     b = dataSets();
     for (i = 0; data[i]; i++) {
         temp = &tree;
         while (*temp) {
               if (data[i] < (*temp)->value)
                  temp = &((*temp)->left);
               else
                   temp = &((*temp)->right);
         }
         *temp = malloc(sizeof(struct node));
         (*temp)->value = data[i];
         (*temp)->left = (*temp)->right = NULL;
     }
     return b; 
}

void pfs (node_pointer t)
{
     
     printf("%c", t->value);
     if (t->left)
        pfs(t->left);
     if (t->right)
        pfs(t->right);
     free(t);
}

int main()
{
    while (dataSets()) {
          pfs(tree);
		  tree = NULL;
          printf("\n");
    }
    pfs(tree);
	tree = NULL;
    printf("\n");
    return 0;
}