Re: Using iterators inside operator <

I'm trying to use iterators inside operator < to compare members of a list.

I cannot get the code below to compile because CScoreSeq has to be const
and there seems to be no way to convince the compiler I'm not going to
modifiy the members of sl or S.sl through iterators.

typedef std::list<CDotSeq> DOTSEQ_LIST;

class CScoreSeq {
public:
   DOTSEQ_LIST sl;

   bool operator<(const CScoreSeq &S) const
   {
      // I need to tell the compiler i1 is not
      // going to modify sl, but how ?
      DOTSEQ_LIST::iterator i1 = sl.begin();
      DOTSEQ_LIST::iterator i2 = S.sl.begin();

      while( true ) {
         if(i1 == sl.end()) {
            if(i2 == sl.end()) return false;
            return true;
         } else if(i2 == sl.end()) {
            return false;
         } else if(*i1 != *i2) {
            return *i1 < *i2;
         } else {
            i1++;
            i2++;
         }
      }
   }

   //...

Any ideas ?