preorder, inorder, and postorder in c | with simple code

PreOrder Traversal:- Root-> Left subtree->Right subtree
InOrder Traversal:- Left subtree -> Root -> Right subtree
PostOrder Traversal:- Lefr subtree -> Right subtree -> Root

 // write a program in c for finding the Inorder, preorder 
// and postorder
 #include <stdio.h>
 #include <stdlib.h>

 struct node
 {
    int data;

    struct node *leftChild;
    struct node *rightChild;
 };

 struct node *root = NULL;

 void insert(int data)
 {
    struct node *tempNode = (struct node *)malloc(sizeof(struct node));
    struct node *current;
    struct node *parent;

    tempNode->data = data;
    tempNode->leftChild = NULL;
    tempNode->rightChild = NULL;

   //if tree is empty
    if (root == NULL)
    {
        root = tempNode;
    }
    else
    {
        current = root;
        parent = NULL;

        while (1)
        {
            parent = current;

            //go to left of the tree
            if (data < parent->data)
            {
                current = current->leftChild;

                //insert to the left
                if (current == NULL)
                {
                    parent->leftChild = tempNode;
                    return;
                }
            } //go to right of the tree
            else
            {
                current = current->rightChild;

                //insert to the right
                if (current == NULL)
                {
                    parent->rightChild = tempNode;
                    return;
                }
            }
        }
    }
  }
  void pre_order_traversal(struct node *root)
  {
    if (root != NULL)
    {
        printf("%d ", root->data);
        pre_order_traversal(root->leftChild);
        pre_order_traversal(root->rightChild);
    }
}

void inorder_traversal(struct node *root)
{
    if (root != NULL)
    {
        inorder_traversal(root->leftChild);
        printf("%d ", root->data);
        inorder_traversal(root->rightChild);
    }
}

void post_order_traversal(struct node *root)
{
    if (root != NULL)
    {
        post_order_traversal(root->leftChild);
        post_order_traversal(root->rightChild);
        printf("%d ", root->data);
    }
  }

  int main()
  {
    int i;
    int array[7] = {27, 14, 35, 10, 19, 31, 42};

    for (i = 0; i < 7; i++)
    {
        insert(array[i]);
    }
    printf("\nPreorder traversal: ");
    pre_order_traversal(root);

    printf("\nInorder traversal: ");
    inorder_traversal(root);

    printf("\nPost order traversal: ");
    post_order_traversal(root);

    return 0;
  }

When the above program is executed, it produces following results --<\b>

   Preorder traversal: 27 14 10 19 35 31 42 
   Inorder traversal: 10 14 19 27 31 35 42 
   Post order traversal: 10 19 14 31 42 35 27