How to self-copy a vector? [duplicate]

Answer 1

My first thought is the following to avoid problems with invalidating iterators.

{   // note: nested scope
    vector temp(vec); // 1st copy
    temp.insert(temp.end(), vec.begin(), vec.end()); // 2nd copy
    temp.insert(temp.end(), vec.begin(), vec.end()); // 3rd copy
    temp.swap(vec); // swap contents before temp is destroyed
}

On review, I think PorkyBrain and Emilio Garavaglia's answers might make more sense.