Sometimes we need to know that, what is the current C++ standard. To get this kind of information, we can use the macro called __cplusplus. For different standards, the value of this will be like below.
| Standard | __cplusplus output |
|---|---|
| C++ pre C++98 | 1 |
| C++98 | 199711L |
| C++98 + TR1 | This cannot be checked, this will be marked as C++98 |
| C++11 | 201103L |
| C++14 | 201402L |
| C++17 | 201703L |
Example
#include<iostream>
int main() {
if (__cplusplus == 201703L)
std::cout << "C++17" << endl;
else if (__cplusplus == 201402L)
std::cout << "C++14" << endl;
else if (__cplusplus == 201103L)
std::cout << "C++11" << endl;
else if (__cplusplus == 199711L)
std::cout << "C++98" << endl;
else
std::cout << "pre-standard C++" << endl;
}Output
C++98