Is there real static polymorphism in C++?

Question

Here is a simple code in C++:

#include 
#include 

template
void function()
{
   std::cout << typeid(T).n         


        

Answer 1

There is no static polymorphism in your example because there is no polymorphism. This is because function() does not look the same as function().

Examples of static polymorphism would include simple function overloading, function templates that can work with type deduction, type traits, and the curiously recurring template pattern (CRTP). So this variation on your example would qualify as static polymorphism:

#include 
#include 

template
void function(T)
{
   std::cout << typeid(T).name() << std::endl;
}

int main()
{
   function(0);   // T is int
   function(0.0); // T is double
   return 0;
}

Here is another example:

template
void function(T t)
{
  t.foo();
}

struct Foo() 
{
  void foo() const {}
};

struct Bar() 
{
  void foo() const {}
};

int main()
{
  Foo f;
  Bar b;
  function(f); // T is Foo
  function(b); // T is Bar
}