View Compilation Error

0_0_18555920_18307.cpp: In function 'void cal_prime()':
0_0_18555920_18307.cpp:12:45: error: 'memset' was not declared in this scope
  memset(prime_flag, true, sizeof(prime_flag));
                                             ^
0_0_18555920_18307.cpp: In function 'int main()':
0_0_18555920_18307.cpp:69:39: error: 'memset' was not declared in this scope
   memset(Map_flag, 0, sizeof(Map_flag));
                                       ^