Iterator gives different results based on usage c++ - c++

Question

I recently started c++ programming. I shifted from Java.
I was building my own Iterable class template like this:
template<class T> class Iterable
{
T start,stop;
public:
explicit Iterable(T s,T e) {start=s; stop=e;;}
public:
virtual void next(T& i) =0;
public:
class iterator: public std::iterator<
std::input_iterator_tag, // iterator_category
T, // value_type
long, // difference_type
const T*, // pointer
T // reference
>{
T current;
Iterable<T>* obj;
public:
explicit iterator(T t,Iterable<T>* o) : obj(o) {current=t;}
iterator& operator++() {obj->next(current); return *this;}
iterator operator++(int) {iterator retval = *this; ++(*this); return retval;}
bool operator==(iterator other) const {return current == other.current;}
bool operator!=(iterator other) const {return !(*this == other);}
const T& operator*() const {return current;}
};
iterator begin() {return iterator(start,this);}
iterator end() {return iterator(stop,this);}
};
When i tried to use this iterator, I got different results when invoked differently:
for(auto S=SI.begin();S!=SI.end();S++)
{
cout << *S << "\n";
//cout << contains(seqs,S) << "\n";
if(!contains(seqs,*S))
seqs.push_back(*(new Sequence(*S)));
}
gave different results from:
for(Sequence S : SI)
{
cout << S << "\n";
//cout << contains(seqs,S) << "\n";
if(!contains(seqs,S))
seqs.push_back(*(new Sequence(S)));
}
even in the loop.
My SeqIter class (SI is object of this class) is as follows:
class SeqIter : public flex::Iterable<Sequence>
{
int n;
public:
SeqIter(int s) : Iterable(Sequence(copyList(0,s),s),Sequence(copyList(3,s),s)) {n=s;}
void next(Sequence& s)
{
char ch;
for(int i=0;i<n;i++)
{
ch=nextBase(s[i]);
s[i]=ch;
if(ch!=0)
break;
}
}
};
Sorry if this is too much code, but I do not know how much code is required.
Also, a brief explanation on the Sequence class:
It is a class that has an array of numbers (in this case I tried with 3), and it generates next sequences based on the first, i.e. 000, 100, 200, 300; 010,110 ...
Each digit ranges from 0-3 (both included)
I am unable to understand why both loops give different sequences (first gives 000 100 200 300 010 110 whereas second gives 000 100 200 300 000 110)
I thought both the loops were fundamentally same, and that the first was just the expansion of the second. Is that not so?
Also sequence class: (Sorry for delay, but I guess this is the problem)
class Sequence
{
int size=1;
char* bps;
public:
Sequence() {size=0;}
Sequence(int s)
{
size=s;
bps=new char[s];
}
Sequence(char* arr,int s)
{
size=s;
bps=arr;
}
Sequence(const Sequence& seq)
{
size=seq.size;
bps=new char[size];
strcpy(bps,seq.bps);
}
String toString() const {return *(new String(bps,size));}
inline char* toCharArray() {return bps;}
inline int getSize() const {return size;}
//operator overloading
public:
bool operator==(const Sequence& s2) const
{
if(s2.size!=size)
return false;
String r1=toString();
String r2=s2.toString();
return (r1==r2 || r1==r2.reverse());
}
inline bool operator!=(const Sequence& s2) const {return !operator==(s2);}
const char& operator[](int n) const
{
if(n>=size)
throw commons::IndexOutOfBoundsException(n,size);
return bps[n];
}
char& operator[](int n)
{
if(n>=size)
throw commons::IndexOutOfBoundsException(n,size);
return bps[n];
}
Sequence& operator=(const Sequence& seq)
{
size=seq.size;
bps=new char[size];
strcpy(bps,seq.bps);
}
};

Answer 1

Sorry everyone. Answering my own question after debugging:
In my Sequence class, I was using strcpy in copying char*, where the array did not end with a '\0'
Probably that caused the error:
I read online a bit more to find that the expansion was as follows:
for(Sequence S : seqs)
{
...
}
is equivalent to
for(auto i=SI.begin();i!=SI.end();i++)
{
Sequence S=*i;
...
}
So in the assignment, (S=*i) the data was not properly copied.
Sorry for all the trouble
fixed by removing assignment operator overload, and changing copy-constructor to:
Sequence(const Sequence& seq)
{
size=seq.size;
bps=new char[size];
for(int i=0;i<size;i++)
bps[i]=seq[i];
}