View Compilation Error

0_0_29929257_12961.cpp:17:1: error: 'set' does not name a type
 set<node>myset;
 ^
0_0_29929257_12961.cpp:18:1: error: 'set' does not name a type
 set<node>::iterator it;
 ^
0_0_29929257_12961.cpp: In function 'int main()':
0_0_29929257_12961.cpp:39:3: error: 'myset' was not declared in this scope
   myset.clear();
   ^
0_0_29929257_12961.cpp:54:8: error: 'it' was not declared in this scope
    for(it=myset.begin();it!=myset.end();it++){
        ^