function_templates

Templates

Templates let us define generic algorithms that are data type independent (i.e., work with ADTs). Templates can be used for functions and classes.

Syntax

Define the template type before the function or class with template <typename T>

Templates define a pattern. The typename <T> is just a placeholder for the actual data type and the compiler will compile all needed versions of the class or function. This can lead to code bloat.

For example the templated data structure std::vector can create

vector<int>, vector<double>, vector<string>, ...

The templated datatype becomes part of the function signature/class name.

Notes:

• Always assume that the template data type may not be a primitive data type so be careful with copying and comparing.
• Always assume that someone will use your class in an ADT, so it needs to provide the Rule of Three!
• Template matching happens at compile time.
• Template matching can be ambiguous which will lead to a compilation error.
• Some template variable names suggest properties of the object:
  • Object: Has a default and copy constructor and can be assigned (operator=).
  • Comparable: Also can be compared with operator<.

Examples:

• Funciton Template
• Class Template