The transform function

- [Narrator] The transform function…is used to run bulk transformations…on elements in a container.…Here I have a working copy of transform.cpp…from chapter four of the exercise files.…The transform template function…is found in the algorithm header…and we'll get back to these template class…and functions at the top here in a minute.…Take a look at the transform function itself.…This version of it takes four arguments.…

The first is a starting point iterator…and its input iterator…so it only needs to end forward.…The second is also an input iterator…for the endpoint of the source container.…So these first two are the begin point…and the endpoint of this first container,…and the third one is the begin point…of the destination container and it is of course…an output iterator.…The fourth argument is an object operator.…It's a unary function, so it's a pointer…to either a function or a object functor…that takes one argument.…

In this case it's pointing to X.…And you see that X is declared up here…as an object of the class accum,…