is_polymorphic template in C++

The std::is_polymorphic template of C++ STL is used to checks whether the type is a polymorphic class type or not. It returns a boolean value showing the same.

Syntax:

template < class T > struct is_polymorphic;

Parameter: This template contains single parameter T (Trait class) to check whether T is a polymorphic class type or not.

Return Value:This template returns a boolean value as shown below:

• True: if the type is a polymorphic class.
• False: if the type is a non-polymorphic class.

Below programs illustrate the std::is_polymorphic template in C++ STL:

Program 1:

// C++ program to illustrate
// std::is_polymorphic template

#include <iostream>
#include <type_traits>
using namespace std;

struct gfg {
    virtual void foo();
};

struct geeks : gfg {
};

class raj {
    virtual void foo() = 0;
};

struct sam : raj {
};

int main()
{
    cout << boolalpha;
    cout << "is_polymorphic:"
         << '\n';
    cout << "gfg:"
         << is_polymorphic<gfg>::value
         << '\n';
    cout << "geeks:"
         << is_polymorphic<geeks>::value
         << '\n';
    cout << "raj:"
         << is_polymorphic<raj>::value
         << '\n';
    cout << "sam:"
         << is_polymorphic<sam>::value
         << '\n';

    return 0;
}

Output:

is_polymorphic:
gfg:true
geeks:true
raj:true
sam:true

Program 2:

// C++ program to illustrate
// std::is_polymorphic template

#include <iostream>
#include <type_traits>
using namespace std;

struct gfg {
    int m;
};

struct sam {
    virtual void foo() = 0;
};

class raj : sam {
};

int main()
{
    cout << boolalpha;
    cout << "is_polymorphic:"
         << '\n';
    cout << "gfg:"
         << is_polymorphic<gfg>::value
         << '\n';
    cout << "sam:"
         << is_polymorphic<sam>::value
         << '\n';
    cout << "raj:"
         << is_polymorphic<raj>::value
         << '\n';

    return 0;
}

Output:

is_polymorphic:
gfg:false
sam:true
raj:true