How can I iterate through a string and also know the index (current position)?

Question

Often when iterating through a string (or any enumerable object), we are not only interested in the current value, but also the position (index). To accomplish this by using

Answer 1

A good practice would be based on readability, e.g.:

string str ("Test string");
for (int index = 0, auto it = str.begin(); it < str.end(); ++it)
   cout << index++ << *it;

Or:

string str ("Test string");
for (int index = 0, auto it = str.begin(); it < str.end(); ++it, ++index)
   cout << index << *it;

Or your original:

string str ("Test string");
int index = 0;
for (auto it = str.begin() ; it < str.end(); ++it, ++index)
   cout << index << *it;

Etc. Whatever is easiest and cleanest to you.

It's not clear there is any one best practice as you'll need a counter variable somewhere. The question seems to be whether where you define it and how it is incremented works well for you.