Thread: Binary Tree Question

You never return back the address of root in the insert to main.either return it or pass as pointer to pointer.
sorry was blitzed earlier. should have spotted that.

Code:

//proc.c
#include  <stdio.h>

struct node
{
   int value;
   struct node *left, *right;
};

void tree_insert(struct node *root, int value);
void tree_destroy(struct node *root);
void tree_print(struct node *root);

void tree_insert(struct node *root, int value)
{
   struct node * temp;

   if(value  < root->value)
   {
    if(root -> left==NULL) {
            temp = (struct node *)malloc(sizeof(struct node));
            if(temp == NULL)
            {
                printf("Could not allocate memory!\n");
                return;
            }
            temp->right = NULL;
            temp->left = NULL;
            temp->value = value;
            printf("Inserted value: %d\n", value);
         root -> left = temp;
            return;
         }
else 
       tree_insert(root->left, value);
   }
   else if(value  > root->value)
   {
    if(root -> right==NULL) {
            temp = (struct node *)malloc(sizeof(struct node));
            if(temp == NULL)
            {
                printf("Could not allocate memory!\n");
                return;
            }
            temp->right = NULL;
            temp->left = NULL;
            temp->value = value;
            printf("Inserted value: %d\n", value);
         root -> right = temp;
            return;
         }
else 
       tree_insert(root->right, value);
   }
}

void tree_destroy(struct node *root)
{
   if(root != NULL)
   {
       tree_destroy(root->left);
       tree_destroy(root->right);
       free(root);
   }
   return;
}

void tree_print(struct node *root)
{
   if(root->left)
   {
       printf("Node value: %d\n", root->value);
       tree_print(root->left);
   }
   if(root->right)
   {
       tree_print(root->right);
   }

}

int main(int argc, char** argv)
{
   struct node *root;
   int i;

   root = NULL;

       root = (struct node *)malloc(sizeof(struct node));
       if(root == NULL)
       {
           printf("Could not allocate memory!\n");
           return;
       }
       root->right = NULL;
       root->left = NULL;
       root->value = 0;

/* if don't allocate memory, you root header is with NULL */
/* And you are sending NULL, not address of NULL*/
/* if you want to send header you can send address of header or make the root extern */

   for(i = 1;i  < 19;i++)
   {
       tree_insert(root, i);
   }

   tree_print(root);

   tree_destroy(root);

   return 0;
}