my assignment says to "Finish the header block on the function.
" What is the header block? Is it the // (write information) or is it something else?

my assignment says to "Finish the header block on the function.
" What is the header block? Is it the // (write information) or is it something else?

It's the very first line of the function. Some also consider the non-required pre:/post: statements to be part of it as well.

i.e.:

int myFunction (double arg1, bool arg2 [, more args])    //<-- the function header
{
   //pre:  precondition1
   //      precondition2

   //post: result1
   //      result2


   //...action statements...
}

Note, if you are going to use a prototype / declaration statement, it must match the header.