How do you delete an element from a vector while iterating?

How do you delete an element from a vector while iterating?

We can do that in many ways:

1. Use the return value of erase() for setting the iterator to the next element.
2. Decrement the iterator after it is passed to the erase() but before erase() is executed.
3. Call erase() on a duplicate of the original iterator after advancing the original iterator to the next element.

What happens to iterator after erase?

After you call erase on an iterator into a std::map , it is invalidated. This means that you cannot use it. Attempting to use it (e.g. by incrementing it) is invalid and can cause anything to happen (including a crash).

Can you remove from a list while iterating?

Even though java. util. ArrayList provides the remove() methods, like remove (int index) and remove (Object element), you cannot use them to remove items while iterating over ArrayList in Java because they will throw ConcurrentModificationException if called during iteration.

How do you delete an element from a vector?

Methods used to remove elements from vector are:

1. vector::pop_back()
2. vector::pop_front()
3. vector::erase()
4. vector::clear()
5. remove(first,last,val)
6. remove_if()
7. remove_copy(first,last,result,val)

How do you remove the last element of a vector?

vector::pop_back()() pop_back() function is used to pop or remove elements from a vector from the back. The value is removed from the vector from the end, and the container size is decreased by 1.

Which of the following method is used to erase the element pointed by the given input iterator?

list erase() function in C++ STL. The list::erase() is a built-in function in C++ STL which is used to delete elements from a list container. This function can be used to remove a single element or a range of elements from the specified list container.

What does vector erase do?

vector::erase() erase() function is used to remove elements from a container from the specified position or range.

How do I know when my iterator is over?

To get the last element in an iterator loop you can use std::next() (from C++11). The loop is generally terminated by iterator != container. end() , where end() returns an iterator that points to the past-the-end element.

Can we modify list while iterating?

Yes, that is a very important point, and all programmers should think about this very carefully. As a general rule in programming, you should avoid mutating an object while iterating over it, unless it is the specific purpose of the function to mutate the original object.

Can we modify Collection while iterating?

It is not generally permissible for one thread to modify a Collection while another thread is iterating over it. Actually, the right way to handle such scenario is to use Iterator to remove the element from the underlying Collection while iterating over it.

Which method is used to remove all elements from vector?

clear() method is used to remove all the elements from a Vector.

How do you know if a vector is empty?

empty() function is used to check if the vector container is empty or not….Algorithm

1. Check if the size of the vector is 0, if not add the back element to a variable initialised as 0, and pop the back element.
2. Repeat this step until the size of the vector becomes 0.
3. Print the final value of the variable.

Is there a way to erase an iterator in C + +?

Something that you can do with modern C++ is using “std::remove_if” and lambda expression; Do not erase and then increment the iterator. No need to increment, if your vector has an odd (or even, I don’t know) number of elements you will miss the end of the vector.

How to erase an element from a vector?

In the line: it2 = uc.erase(it2); an element pointed by iterator it2is removed from the vector, elements are shifted in memory in order to fill that gap which invalidates it2. it2gets a new value and now points to the first element after the the removed one or the end of the vector (if removed element was the last one).

When to return Iterator from a.erase ( Q )?

Quoting from the standard from 23.1.1/7: The iterator returned from a.erase(q) points to the element immediately following q prior to the element being erased. If no such element exists, a.end() is returned.

Is the iterator valid after uc.erase?

The iterator itis not valid after uc.erase, so subsequent ++ and use might result in runtime error. Similarly, even though you assign the result of erase to it2, the call can invalidate it, which is not changed.