View Compilation Error

0_0_38550654_19534.cpp: In function 'int main()':
0_0_38550654_19534.cpp:9:29: error: unable to find numeric literal operator 'operator""B'
     {t=sqrt((x2-x1)*(x2-x1)%2B(y2-y1)*(y2-y1));
                             ^
0_0_38550654_19534.cpp:9:29: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes