Skydiver, on 19 March 2013 - 10:29 AM, said:

Indeed it is simple. Thanks for the help!

Still can't get it and confused. This is my thinking. You start at the root node and you add data to it. The if you want to add data which is smaller you go to the left subtree. So because I have defined current as equal to the root node I need to get to that left subtree node. So I do this;

current = current->left;

Since then I'm at the a node which is NULL I add data to this node like this:

current->item = data;

Skydiver, on 12 November 2012 - 02:52 PM, said:

Surely I need that on line 29 so that data is added to that current node?

Hello,

I'm running into some more trouble with this add method. Just trying to do the second part. I get an error something to do with not allocating memory or something like that on the line. Could you point me in the right direction please.

current->item = data;

struct TreeNode *insertion(int data, TreeNode *current)
{
    if(root == NULL)
    {
        root = (struct TreeNode*)malloc(sizeof(struct TreeNode));
        root->item = data;  
        root->left = NULL;
        root->right = NULL;
    }
    else
    {
        current = root;
        while(current != NULL)
        {
                if (data == current->item)
                {
                    printf("No Duplicate Values.");
                    return 0;
                }
                else if(data < current->item)
                {
                    current = current->left;
                }
                else if(data > current->item)
                {
                    current = current->right;
                }
        }
        current->item = data;
    }
}

Hello,

Don't worry I got it? Thanks for jogging my memory.
Solution:

#include <stdio.h>
#include <stdlib.h> 
typedef struct TreeNode 
{
        int item;         // The data in this node.
        struct TreeNode *left;   // Pointer to the left subtree.
        struct TreeNode *right;  // Pointer to the right subtree.
}TreeNode;
TreeNode *root = NULL;

struct TreeNode *insertion(int data)
{
    if(root == NULL)
    {
        root = (struct TreeNode*)malloc(sizeof(struct TreeNode));
        root->item = data;  
        root->left = NULL;
        root->right = NULL;
    }
}
     
void print(struct TreeNode *node)
{
        if(node == NULL)
        {
                return;
        }
        print(node->left);
        printf("%d ",node->item);
        print(node->right);

}

void menu()
{
        
	int temp = 1;
	while(temp == 1)
        {
                //Prints out the Menu
                int i;
                printf("");
                printf("*** Binary Tree Assignment ***\n");
                printf("Press 'i' to insert an element into the hash table\n");
                printf("Press 'd' to delete an element from the hash table\n");
                printf("Press 'l' to look up an element in the hash table\n");
                printf("Press 's' to obtain the size of the table\n");
                printf("Press 'p' to print the current table\n");
                printf("Press 'e' to exit from the program\n");
                printf("Enter a choice:\n");
		char input;
                scanf("%c", &input); //Getting user input for there selection
		switch(input)
		{
			//Insertion
			case 'i': printf("Type the integer you wish to enter into the hashTable:\n");	
                                  scanf("%d", &i);
                                  insertion(5);
				  break;
			//Deletion
			case 'd': printf("Type the integer you wish to delete from the hashTable:\n");
                                  scanf("%d", &i);
		        	  break;
			//Size
			case 's': 
				  break;
			//Print
			case 'p': print(root);
				  break;
			//Exit
                        case 'e': temp = 0;
                                  break;
			//If incorrect selection is made
			default:  printf("Error: Wrong selection, choose again\n");
				  break;
		}
        }
}

int main()
{
    menu();
    return 0;
}