View Compilation Error

0_0_13807107_20337.cpp: In function 'int main()':
0_0_13807107_20337.cpp:23:36: error: 'memset' was not declared in this scope
         memset(num , 0 ,sizeof(num));
                                    ^
0_0_13807107_20337.cpp:49:52: error: 'pow' was not declared in this scope
             if(re[i])      printf(" %.lf",pow(3.0,i));
                                                    ^
0_0_13807107_20337.cpp:54:49: error: 'pow' was not declared in this scope
         if(num[i] == 1) printf(" %.lf",pow(3.0,i));
                                                 ^