I have learn c++ ...so i need to learn c# ..if yes then why... please reply

Answer 1

You are not required to learn C# just because you learned C++. What to do or learn next depends on what it is you want to accomplish with programming.

Answer 2

There are some C++ programmers who don't use C# and vice versa.

Answer 3

Learning C Tic Tac Toe after C-- is not necessary, you could learn many programming languages like C, Minecraft Java Edition, Cobra, Coffee etc after C Tic Tac Toe.