How can I use unique with STL vectors in C++?

How can I use the unique function with STL vectors in C++?

You can use the std::unique function to remove consecutive duplicate elements from a vector. It rearranges the elements and returns an iterator to the new end of the vector.

Can you show me a code example?

Sure! Here's a simple example:

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    std::vector<int> vec = {1, 2, 2, 3, 4, 4, 4, 5};
    std::sort(vec.begin(), vec.end()); // Sort the vector first
    auto last = std::unique(vec.begin(), vec.end());
    vec.erase(last, vec.end()); // Remove duplicates

    for (int n : vec) {
        std::cout << n << ' ';
    }
    return 0;
}

What happens if the vector is not sorted?

If the vector is not sorted, std::unique will only remove consecutive duplicates. Non-consecutive duplicates will remain in the vector.

Is there a way to remove all duplicates regardless of order?

Yes, you can use a combination of std::sort, std::unique, and std::erase to remove duplicates, or you can use a std::set to automatically handle duplicates.