• Remember a data type is a set of values, along with operations on those values.
• From chapter 3:
• 
• As you will note, we have one more simple type: enum
• Two address types:pointer and reference
• And the structured types
  • both string and stream are class types.
• The simple types are known as atomic types
  • This is because we can't break them up any further.
  • As opposed to the string, which we can break into characters
• If you have not yet seen the sizeof function:
  • std::size_t sizeof(type)
  • std::size_t sizeof(expression)
  • This returns the size, in bytes
• typedef allows you to rename a data type.S
  • typedef existing_data_type identifier;
  • Here we don't really create a new data type, we just rename an existing one
  • This is done in the declaration area (constants, function prototypes, ...)
  • Probably before any of those pieces.
  • I like to follow the function naming conventions, but end with a T
    • typedef float NewNumberT;
  • After declared, they can be used as a normal type.
    • MyNumberT functionOne(MyNumberT x, MyNumberT y);
    • const MyNumberT A_VALUE = 3.423;
    • MyNumberT base;
• Enumerated types
  • look at problem 1 page 493.
  • How will we store the planet?
    • A string?
    • An integer (as in Hangman?)
    • Both of these seem less than satisfying.
  • C++ provides another way to accomplish this
    • An enumerated type is a user-defined data type whose domain is an ordered set of literal values expressed as identifiers.
    • enum identifier {enumerator_list}
    • an enumerator is one of the values in the list.
    • An enumerator is an identifier, followed by an optional assignment to an integer or another enumerator.
    • By default the first value is 0
    • And each value after that is the previous + 1.
  • Enumerated types
  • There is no default I/O on enumerated types. (They act as integers)
  • Comparison works.
  • Math does not work (++, +=, ...)
  • They can be passed as parameters and returned as values of functions.