How can I make swap function faster in c++ ?

Question

I am writing a couple string sort algorithm with c++ and I wonder if I can make this swap operation faster.

void swap(string *items,int a, int b ){
        string temp;
        temp = items[a];
        items[a] = items[b];
        items[b] = temp;
}

I'll be appreciate if you can help...

Answer 1

String class has its own swap function.

items[a].swap(items[b]);

It's the fastest way to do this because it accesses the string internals and avoids all copying.

See here.

Answer 2

You can use std::swap():

void swap(string *items, int a, int b) {
    std::swap(items[a], items[b]);
}

But there's no guarantee that this will be measurably faster, and this probably isn't the slow part of your code anyway. Have you measured the performance of the swap operation compared to the rest of your code?