CODEWITHSUNDEEP
c++
Invictus
Invictus

Reputation: 4328

Iteration over std::set does not end

Today i was trying to print elements of a set , Which went into an infinite loop . When i tried to fetch the size of set , it returned me correct value which was 8.

the code was like this 

     std::cout << "size of set is " << myset.size();
     for(it=myset.begin();it!=myset.end();it++)
     std::cout << "value is : " << *it;

iterator it was declared above before fetching the size . And one of the interesting fact was that one of the expected element was missing from set while printing it.

I know i would appear mad to you or making some silly mistake but my concern is that is it possible that myset.end() points to some random place ? But even though so why was it repeating the elements from set while printing and not crashing

Upvotes: 1

Views: 711

Answers (1)

John Humphreys
John Humphreys

Reputation: 39254

The .end() iterator returned by all STL containers points to one-past-the-end of the container, and dereferencing it (*iterator) results in undefined behavior.

Your for loop will not dereference .end() though as it stops when your iterator equals .end(), so this should not be a problem in the code you've posted. You probably had a different mistake in your other code earlier.

Upvotes: 1

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