View Compilation Error

0_0_18727193_12249.cpp: In function 'int main()':
0_0_18727193_12249.cpp:12:23: error: unable to find numeric literal operator 'operator""n'
         printf("%d\n",2n-4);
                       ^
0_0_18727193_12249.cpp:12:23: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes