Access index in range-for loop

Question

I have a vector of objects and am iterating through it using a range-for loop. I am using it to print a function from the object, like this:

vector

        

Answer 1

You can use the enumerate view of range-v3:

std::vector storedValues;
for (auto const& [idx, value] : storedValues | ranges::view::enumerate) {
  std::cout << idx << ": " << value << '\n';
}

In C++20 will introduce additional initializations in range-for loops:

std::vector storedValues;
for (size_t idx = 0; auto value : storedValues) {
  std::cout << idx << ": " << value << '\n';
  ++idx;
}