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C++ Function Templates
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by: Muthukumar
C++ Function
templates are those functions which can handle different data
types without separate code for each of them. For a similar
operation on several kinds of data types, a programmer need
not write different versions by overloading a function. It is
enough if he writes a C++ template based function. This will
take care of all the data types.
There are
two types of templates in C++, viz., function templates and
class templates. This article deals with only the function templates.
There are
lot of occasions, where we might need to write the same functions
for different data types. A favorite example can be addition
of two variables. The variable can be integer, float or double.
The requirement will be to return the corresponding return type
based on the input type. If we start writing one function for
each of the data type, then we will end up with 4 to 5 different
functions, which can be a night mare for maintenance.
C++ templates
come to our rescue in such situations. When we use C++ function
templates, only one function signature needs to be created.
The C++ compiler will automatically generate the required functions
for handling the individual data types. This is how a programmer's
life is made a lot easier.
C++ Template
functions - Details:
Let
us assume a small example for Add function. If the requirement
is to use this Add function for both integer and float, then
two functions are to be created for each of the data type (overloading).
int
Add(int a,int b) { return a+b;} // function Without C++ template
float Add(float a, float b) { return a+b;} // function Without
C++ template
If there
are some more data types to be handled, more functions should
be added.
But if we
use a c++ function template, the whole process is reduced to
a single c++ function template. The following will be the code
fragment for Add function.
template
T Add(T a, T b) //C++ function template sample
{
return a+b;
}
This c++
function template definition will be enough. Now when the integer
version of the function, the compiler generates an Add function
compatible for integer data type and if float is called it generates
float type and so on.
Here T is
the typename. This is dynamically determined by the compiler
according to the parameter passed. The keyword class means,
the parameter can be of any type. It can even be a class.
C++ Template
functions - Applicability:
C++
function templates can be used wherever the same functionality
has to be performed with a number of data types. Though very
useful, lots of care should be taken to test the C++ template
functions during development. A well written c++ template will
go a long way in saving time for programmers.
About
The Author
Muthukumar
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can be found at http://www.codersource.net/.
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