Delete a Binary Tree

Using postorder traversal , delete tree , as we should delete child nodes first instead of parent node for straight tree deletion
#include<stdio.h>


#include<stdlib.h>


struct treeNode
{
    int data;
    struct treeNode* left;
    struct treeNode* right;

};   


struct treeNode* newNode(int n)
{
    struct treeNode* node = (struct treeNode*) malloc(sizeof(struct treeNode));
    node->data = n;
    node->left = NULL;
    node->right = NULL;
    return  node;

}

void deleteTree(struct treeNode* node)
{
    if (node == NULL)
    {
        return;
    }

    deleteTree(node->left);
    deleteTree(node->right);
    free(node);

}
int main()
{
    struct treeNode *root = newNode(1);
    root->left = newNode(2);
    root->right = newNode(3);
    root->left->left = newNode(4);
    root->left->right = newNode(5);

    deleteTree(root);
    root = NULL;

    printf("\n Tree deleted ");

    getchar();
    return 0;
   
}