Here's simplest C++ solution I could write

#include<queue>

void LevelOrder(node * root)
{

    queue<node*> q;
    node *temp = root;

    while(temp!=NULL)
{ 
        cout<<temp->data<<" ";
        if(temp->left!=NULL)
            q.push(temp->left);
        if(temp->right!=NULL)
            q.push(temp->right);

         temp = q.front();  
        q.pop();
}