View Compilation Error

0_0_13270257_8252.cpp: In function 'int main()':
0_0_13270257_8252.cpp:33:30: error: 'sqrt' was not declared in this scope
   for (int j = 2; j <= sqrt(i); j++)
                              ^
0_0_13270257_8252.cpp:42:33: error: 'memset' was not declared in this scope
   memset(visit, 0, sizeof(visit));
                                 ^