Templates

• Alows functions and classes to work with many different data types without the programmer having to write a separate version for each type.
• For classes, it is a mechanism that describes how to create one type given another type as a parameter.
• Arguments of a template do not need to be related by inheritance.
• Common uses are container classes (e.g. List).
• Unlikely one would want just a list of a certain type.
• Templates allow the generalization of a list of a certain type (e.g. int) to a list of anything.
• template < class T >
• T is used as any other type name
• Scope of T extends to the end of the declaration it prefixes.
• Pair template example
• Template Instantiation class delcarlation from template class and the template argument.
• Specialization version of a template corresponding to a particular template argument.
• Class generated from templates is just like any other class
• No additional runtime mechanisms.
• No reduction in generated code.
• Standard template abstractions are commonly represented as templates (e.g. string, ostream).
• Function Templates
• swap() function example
• sorting example (sort.cpp, 16-02.cpp)
• Resolving Ambiguities
• Explicit qualification
• Adding appropriate declarations
• Hints
• Write a concrete class/function without templates first. Then once the concrete example is debugged generalize it into the templated version.
• Other examples
• PFArray (16-07.cpp, pfarray.cpp, pfarray.h)
• PFArrayBak (16-10.cpp, pfarraybak.cpp, pfarraybak.h)

HW7

• Questions???

Additional Notes