View Compilation Error

0_0_30027141_31657.cpp: In member function 'void FT::clear()':
0_0_30027141_31657.cpp:22:29: error: 'memset' was not declared in this scope
         memset(a,0,sizeof(a));
                             ^
0_0_30027141_31657.cpp: In function 'int main()':
0_0_30027141_31657.cpp:53:25: error: 'sort' was not declared in this scope
         sort(bnum,bnum+n);
                         ^
0_0_30027141_31657.cpp:54:36: error: 'unique' was not declared in this scope
         int rlen=unique(bnum,bnum+n)-bnum;
                                    ^