CODEWITHSUNDEEP
c++
Anycorn
Anycorn

Reputation: 51445

C++ for-range loop

I was playing with range loops, eg:

for (auto i : range) {

which is equivalent to

auto it = range.begin();
auto i = *it;

but what i want is this:

for (auto it : range) {
    *it; // the it var is not derefernced by range loop

is there a way to accomplish this? maybe something like:

for (auto it : make_range(range)) {
    *it; // the it var is not derefernced by range loop

....

One solution I found so far is using boost::irange, eg:

for (auto it : irange(range.begin(), range.end())) {

Upvotes: 3

Views: 334

Answers (1)

Remy Lebeau
Remy Lebeau

Reputation: 595652

The whole purpose of a for-range loop is to iterate through the contents of a container. So no, there is no native means to gain access to the iterator used by the loop. If you need that, you should not be using a for-range loop to begin with. The only option to gain access to a container iterator in a for-range loop is to write a custom adapter class that wraps the container and exposes its own iterators that return container iterators when dereferenced. Then you iterate through the adapter instead of the container directly.

Upvotes: 4

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