is_abstract Class

Tests if type is abstract class.

template<class Ty>
    struct is_abstract;

Parameters

• Ty
  The type to query.

Remarks

An instance of the type predicate holds true if the type Ty is a class that has at least one pure virtual function, otherwise it holds false.

Example

// std_tr1__type_traits__is_abstract.cpp 
// compile with: /EHsc 
#include <type_traits> 
#include <iostream> 
 
struct trivial 
    { 
    int val; 
    }; 
 
struct abstract 
    { 
    virtual int val() = 0; 
    }; 
 
int main() 
    { 
    std::cout << "is_abstract<trivial> == " << std::boolalpha 
        << std::is_abstract<trivial>::value << std::endl; 
    std::cout << "is_abstract<abstract> == " << std::boolalpha 
        << std::is_abstract<abstract>::value << std::endl; 
 
    return (0); 
    } 
 

is_abstract<trivial> == false
is_abstract<abstract> == true

Requirements

Header: <type_traits>

Namespace: std

See Also

Reference

<type_traits>

is_polymorphic Class

Other Resources

<type_traits> Members