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 string::iterator we have to maintain a separate index:

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

The style shown above does not seem superior to the 'c-style':

string str ("Test string"); for ( int i = 0 ; i < str.length(); i++) {     cout << i << str[i] ; } 

In Ruby, we can get both content and index in a elegant way:

"hello".split("").each_with_index {|c, i| puts "#{i} , #{c}" } 

So, what is the best practice in C++ to iterate through an enumerable object and also keep track of the current index?

Answer 1

Like this:

     std::string s("Test string");     std::string::iterator it = s.begin();      //Use the iterator...     ++it;     //...      std::cout << "index is: " << std::distance(s.begin(), it) << std::endl;