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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.
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