C++ "function" teaching aid
Look at the following code. There's a main function inside which there's a call to a function called doubling that returns twice the given number. You need to write a prototype for the doubling function and complete the function itself. Type something in the boxes so that the compiled code would work
P.S. the checker isn't foolproof. The best way to check your answer is to
put the program into a file, compile it, then run it!