binarysearchtree.c

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

typedef struct BST
{
    int data;
    struct BST *left;
    struct BST *right;
} node;

node *create();
void insert(node *, node *);
void preorder(node *);

int main()
{
    char ch;
    node *root = NULL, *temp;

    do
    {
        temp = create();
        if (root == NULL)
            root = temp;
        else
            insert(root, temp);

        printf("Do you want to enter more(y/n)?");
        getchar();
        scanf("%c", &ch);
    } while (ch == 'y' | ch == 'Y');

    printf("Preorder Traversal: ");
    preorder(root);
    return 0;
}

node *create()
{
    node *temp;
    printf("Enter data:");
    temp = (node *)malloc(sizeof(node));
    scanf("%d", &temp->data);
    temp->left = temp->right = NULL;
    return temp;
}

void insert(node *root, node *temp)
{
    if (temp->data < root->data)
    {
        if (root->left != NULL)
            insert(root->left, temp);
        else
            root->left = temp;
    }

    if (temp->data > root->data)
    {
        if (root->right != NULL)
            insert(root->right, temp);
        else
            root->right = temp;
    }
}

void preorder(node *root)
{
    if (root != NULL)
    {
        printf("%d ", root->data);
        preorder(root->left);
        preorder(root->right);
    }
}