Separate the code into three part, header file, cpp file main file

#include using namespace std; /* A binary tree node has data, pointer to left child and a pointer to right child */ class node { public: int data; node *left; node *right; }; // A utility function to create a node node* newNode (int data) { node* temp = new node(); temp->data = data; temp->left = temp->right = NULL; return temp; } // A recursive function to construct Full from pre[] and post[]. // preIndex is used to keep track of index in pre[]. // l is low index and h is high index for the current subarray in post[] node* constructTreeUtil (int pre[], int post[], int* preIndex, int l, int h, int size) { // Base case if (*preIndex >= size || l > h) return NULL; // The first node in preorder traversal is root. So take the node at // preIndex from preorder and make it root, and increment preIndex node* root = newNode ( pre[*preIndex] ); ++*preIndex; // If the current subarray has only one element, no need to recur if (l == h) return root; // Search the next element of pre[] in post[] int i; for (i = l; i <= h; ++i) if (pre[*preIndex] == post[i]) break; // Use the index of element found in postorder to divide // postorder array in two parts. Left subtree and right subtree if (i <= h) { root->left = constructTreeUtil (pre, post, preIndex, l, i, size); root->right = constructTreeUtil (pre, post, preIndex, i + 1, h-1, size); } return root; } // The main function to construct Full Binary Tree from given preorder and // postorder traversals. This function mainly uses constructTreeUtil() node *constructTree (int pre[], int post[], int size) { int preIndex = 0; return constructTreeUtil (pre, post, &preIndex, 0, size - 1, size); } // A utility function to print inorder traversal of a Binary Tree void printInorder (node* node) { if (node == NULL) return; printInorder(node->left); cout<data<<" "; printInorder(node->right); } // Driver program to test above functions int main () { int pre[] = {1, 2, 4, 8, 9, 5, 3, 6, 7}; int post[] = {8, 9, 4, 5, 2, 6, 7, 3, 1}; int size = sizeof( pre ) / sizeof( pre[0] ); node *root = constructTree(pre, post, size); cout<<"Inorder traversal of the constructed tree: "; printInorder(root); return 0; }