Function Specialization

Question

I try to figure out what is difference between this to function.

First one is template function for adding to expression :

template <class T,class Y,class Z>
Z add(T t,Y y)
{
  return t+y;
}

Specialization_1 :

template<>
int add<int,int,int>(int t,int y)
{

    return t+y+10000;
}

Specialization_2 :

int add(int t,int y)
{

    return t+y+10000;
}

What difference is between speciaization_1 and specialization_2 ? Is it necessary to use template<> before declaration????

Answer 1

the first is Specialization. the second is overloading.

the first will create a special varient of the template. and the second will create another function with the same name

Answer 2

I don't see interest in your first specialization. this is more useful for example:

template <typename T>
T add(T t,T y)
{
  return t+y+10000;
}

Now you can use this function add for many differents type.