Intro to Templates

• This is chapter 12, you should read it.
• We discuss templates
  • These are plans for implementing classes and functions.
  • This is the way c++ supports generic programming.
• Generic programming allows to write code in a to-be-sepecified-later datatype
  • The template is a blue-print for the code.
  • When the compiler detects that we need new code based on the template, it will write it for us.
• We will just be covering the basics in the next few days.
  • There is more
  • And it is changing.
• The general idea that templates allow us to parameterize classes and functions for types just like we do for data values.
• Warning: we will be putting what looks like code in .h files.
  • This is NOT the case.
  • If "code" is enclosed in a template structure, it is not code.
  • It is a blueprint.
  • The compiler will use this to generate the actual code.
• Basic syntax:
  • template < typename T> declaration;
  • template < class T> declaration;
  • template < typename T, typename Q> declaration;
• The T will then become a stand-in for a type.
• I am going to skip ahead to 447 for function templates.
• The base example is usually the min function
  • This take two items of the same type and returns the smallest.
  • This assumes that the < operator is defined on this type.
  • There is code in development to control this, but we will just assume it to be true for our discussions.
• Examples in MinT.h
• By the way, there is an algorithm section of the standard library
  • Many of the algorithms you need will be there.
  • Most are templated.
  • min is there.
  • Look at the man page for min
  • We will look at this later.