View Compilation Error

0_0_17616448_21787.cpp:6:12: error: 'std::memset' has not been declared
 using std::memset;
            ^
0_0_17616448_21787.cpp: In function 'int main()':
0_0_17616448_21787.cpp:54:29: error: 'memset' was not declared in this scope
   memset(res, 0, sizeof(res));
                             ^