decltype() in c++ causes compile errors

Question

I am new to c++. In a tutorial i was reading about auto and decltype and tried the following:

#include <iostream>

using namespace std;

int foo = 0;
decltype(foo) bar; 
bar = 22;


int main(){
    cout<<foo;
    cout<<bar;
    }

and i get this error upon compilation:

tst.cpp.6:1: warning: identifier 'decltype' is a keyword in C++11

Why is this happening?

Did you explicitly enable c++11 features in your build chain? — StoryTeller - Unslander Monica, Apr 23 '16 at 21:38
Btw, it's not an error, it's a warning. Difference: Error = something is wrong, compilation was aborted. Warning = something looks suspicious to the compiler, but it has continued compilation anyway. — HolyBlackCat, Apr 23 '16 at 23:00

score 4 · Accepted Answer · edited May 23 '17 at 11:59

4

You need to add -std=c++11 flag (command line argument) to your compiler:

g++ -std=c++11 tst.cpp -o your_program_name.exe

edited May 23 '17 at 11:59

Community

answered Apr 23 '16 at 21:38

gdlmx

1 Answers1