#include <iostream>
#include <queue>

template <typename T>
class BinaryTreeNode {
   public:
    T data;
    BinaryTreeNode<T>* left;
    BinaryTreeNode<T>* right;

    BinaryTreeNode(T data) {
        this->data = data;
        left = NULL;
        right = NULL;
    }
};

using namespace std;


BinaryTreeNode<int>* takeInput() {
    int rootData;

    cin >> rootData;
    if (rootData == -1) {
        return NULL;
    }
    BinaryTreeNode<int>* root = new BinaryTreeNode<int>(rootData);
    queue<BinaryTreeNode<int>*> q;
    q.push(root);
    while (!q.empty()) {
        BinaryTreeNode<int>* currentNode = q.front();
        q.pop();
        int leftChild, rightChild;

        cin >> leftChild;
        if (leftChild != -1) {
            BinaryTreeNode<int>* leftNode = new BinaryTreeNode<int>(leftChild);
            currentNode->left = leftNode;
            q.push(leftNode);
        }

        cin >> rightChild;
        if (rightChild != -1) {
            BinaryTreeNode<int>* rightNode =
                new BinaryTreeNode<int>(rightChild);
            currentNode->right = rightNode;
            q.push(rightNode);
        }
    }
    return root;
}
void printLevelWise(BinaryTreeNode<int> *root) {
	// Write your code here
    queue<BinaryTreeNode<int>*> pendingNodes;
    pendingNodes.push(root);
    while(pendingNodes.size()!=0){
		BinaryTreeNode<int>* front = pendingNodes.front();
        pendingNodes.pop();
        cout<<front->data<<":";
        if(front->left!=NULL){
        	cout<<"L"<<front->left->data<<",";
            pendingNodes.push(front->left);
        }
        else if(front->left==NULL){
          cout<<"L"<<"-1"<<",";
        }
        if(front->right!=NULL){
			cout<<"R"<<front->right->data;
            pendingNodes.push(front->right);
        }
        else if(front->right == NULL){
          cout<<"R"<<"-1";
        }
       cout<<endl; 
       
    }
}
int main() {
    BinaryTreeNode<int>* root = takeInput();
    printLevelWise(root);
}
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Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}