View Compilation Error

0_0_26417351_28910.cpp: In function 'int main()':
0_0_26417351_28910.cpp:25:35: error: 'qsort' was not declared in this scope
         qsort(a,n,sizeof(node),cmp);
                                   ^
0_0_26417351_28910.cpp: At global scope:
0_0_26417351_28910.cpp:40:2: error: expected unqualified-id before '<' token
 }<span style="color:#ff0000;">
  ^