Is there any way to tell if a template parameter is a specific base data type like int or unsigned int? std::is_base_of doesn't do it, tried that. I'd like to write collections that can box all the basic data types but I can't find a way to tell which type it is...
Use is_same. If you don't have an implementation (std or boost) then use this:
template < typename T1, typename T2 >
struct is_same { enum { value = false }; };
template < typename T >
struct is_same <T,T> { enum { value = true }; };
Some useful ones:
If you need some more narrow definiton, you can OR several std::is_same
traits together, eg
template<typename T>
struct is_int_or_char_or_float {
static const bool value =
std::is_same<T, int>::value ||
std::is_same<T, char>::value ||
std::is_same<T, float>::value;
};
If you want to know whether it is of a specific type, you could use std::is_same
:
#include <type_traits>
bool isInt = std::is_same<int, T>::value;
If you wanted to know whether it is any integral type, the std::is_integral
bool isInt = std::is_integral<T>::value;
you can use this code:
#include <typeinfo>
#include <iostream>
class someClass { };
int main(int argc, char* argv[]) {
int a;
someClass b;
std::cout<<"a is of type: "<<typeid(a).name()<<std::endl; // Output 'a is of type int'
std::cout<<"b is of type: "<<typeid(b).name()<<std::endl; // Output 'b is of type someClass'
return 0;
}
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.