For outdated compilers...

• Older compilers (think older C++ programs) may not support initialization of integral static variables in declaration.

• The usual external static member initialization compiles fine, but still can't be used for array sizes.

• Use the "enum hack" instead:

  
  class IntStack
  {
      enum { STACK_SIZE = 1024 }; // nameless enum
      int m_stack[ STACK_SIZE ];  // works fine!
  };