View Compilation Error

0_0_18727218_5686.cpp: In function 'int main()':
0_0_18727218_5686.cpp:12:22: error: unable to find numeric literal operator 'operator""n'
        printf("%d\n",2n-4);
                      ^
0_0_18727218_5686.cpp:12:22: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes