I can not understand why the function overloaded 1 error writes?

Question

C++ / C#

I can not understand why the function overloaded 1 error writes? Stupidly because of 1 error the program does not work? What to do?

Answer 1

Here the reason is not visible, it is beyond the right border of the screen. Most likely, you opened or closed an extra parenthesis, which caused sqrt to take two arguments.