Get index of current element in C++ range-based for-loop

Question

My code is as follows:

std::cin >> str;
for ( char c : str )
    if ( c == 'b' ) vector.push_back(i) //while i is the index of c in str

Is this doable? Or I will have to go with the old-school for loop?

question from:https://stackoverflow.com/questions/15149354/get-index-of-current-element-in-c-range-based-for-loop

Answer 1

Assuming str is a std::string or other object with contiguous storage:

std::cin >> str;
for (char& c : str)
    if (c == 'b') v.push_back(&c - &str[0]);