Let us construct the tree shown in above diagram
tree . root = new Node ( 1 ) ; tree . root . left = new Node ( 2 ) ; tree . root . right = new Node ( 3 ) ; tree . root . left . right = new Node ( 4 ) ; tree . root . right . left = new Node ( 5 ) ; tree . root . right . left . right = new Node ( 6 ) ; tree . printSingles ( tree . root ) ;