C++ for Scientists - Technische Universität Dresden

Generic programming
Chapter 4
In this chapter we will explain the use of templates in C ++ to create generic functions and
classes. We will also discuss metaprogramming and the Standard Template Library.
4.1 Templates
Templates are a feature of the C ++ programming language that create functions and classes
that operate with generic types — also called parametric types. As a result, a function or class
can work with many different data types without being manually rewritten for each one.
A template parameter is a special kind of parameter that can be used to pass a type as an
argument: just like regular function parameters can be used to pass values to a function,
template parameters allow to pass also types to a function or a class. These generic functions
can use these parameters as if they were any other regular type.
4.2 Generic functions
Generic functions — also called function templates — are in some sort generalizations of overloaded
functions.
Suppose we want to write the function max(x,y) where x and y are variables or expressions of
some type. Using overloading, we can easily do this as follows:
int inline max (int a, int b)
{
if (a > b)
return a;
else
return b;
}
double inline max (double a, double b)
{
if (a > b)
return a;
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