count_and_sum_of_nodes.cpp

#include<bits/stdc++.h>
using namespace std;

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

    Node(int val) {
        data = val;
        left = NULL;
        right = NULL;
    }
};

int countNodes(Node* root) {
    if(root == NULL) {
        return 0;
    }

    return countNodes(root->left) + countNodes(root->right) + 1;
}

int sumOfNodes(Node* root) {
    if(root == NULL) {
        return 0;
    }

    return sumOfNodes(root->left) + sumOfNodes(root->right) + root->data;
}

int main() {

    Node* root = new Node(1);
    root->left = new Node(2);
    root->right = new Node(3);
    root->left->left = new Node(4);
    root->left->right = new Node(5);
    root->right->left = new Node(6);
    root->right->right = new Node(7);

    cout<<countNodes(root)<<endl;
    cout<<sumOfNodes(root)<<endl;

    return 0;
}