Let us check the values of nextRight pointers
Console . WriteLine ( " Following ▁ are ▁ populated ▁ nextRight ▁ pointers ▁ in ▁ " + " the ▁ tree " + " ( -1 ▁ is ▁ printed ▁ if ▁ there ▁ is ▁ no ▁ nextRight ) " ) ; int a = tree . root . nextRight != null ? tree . root . nextRight . data : - 1 ; Console . WriteLine ( " nextRight ▁ of ▁ " + tree . root . data + " ▁ is ▁ " + a ) ; int b = tree . root . left . nextRight != null ? tree . root . left . nextRight . data : - 1 ; Console . WriteLine ( " nextRight ▁ of ▁ " + tree . root . left . data + " ▁ is ▁ " + b ) ; int c = tree . root . right . nextRight != null ? tree . root . right . nextRight . data : - 1 ; Console . WriteLine ( " nextRight ▁ of ▁ " + tree . root . right . data + " ▁ is ▁ " + c ) ; int d = tree . root . left . left . nextRight != null ? tree . root . left . left . nextRight . data : - 1 ; Console . WriteLine ( " nextRight ▁ of ▁ " + tree . root . left . left . data + " ▁ is ▁ " + d ) ; } }