Main.cc: In function 'int main()': Main.cc:10:19: error: unable to find numeric literal operator 'operator""i' for( int i=1;i<=1i++) ^ Main.cc:10:19: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes Main.cc:10:23: error: expected ';' before ')' token for( int i=1;i<=1i++) ^