View Compilation Error

0_0_17809363_8873.cpp: In function 'int main()':
0_0_17809363_8873.cpp:59:44: error: 'qsort' was not declared in this scope
         qsort(d+1,n,sizeof(struct node),cmp);
                                            ^
0_0_17809363_8873.cpp:92:29: error: 'memset' was not declared in this scope
         memset(b,0,sizeof(b));
                             ^