View Compilation Error

0_0_17781037_5957.cpp: In function 'int main()':
0_0_17781037_5957.cpp:16:29: error: unable to find numeric literal operator 'operator""a'
    ans += s * (100.0 - p) / 100a;
                             ^
0_0_17781037_5957.cpp:16:29: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes