Question

I need an analog of Haskell’s foldl function to fold any STL containers. Expected signature is like following:

template Iterator, FoldingFunction, Result
Result foldl(
  Iterator begin, 
  Iterator end, 
  FoldingFunction f, 
  Result initValue);

Standard STL has no such function. Does Boost have any?

I know it’s pretty simple to implement, but I’d like to know whether there’s any ready standardized implementation.

And one more question: how do you usually fold data lists in C++/STL?

Answer 1

STL does have such a function: std::accumulate. However, it is in the header <numeric>, not <algorithm>.

Actually the Wikipedia page on “Fold” already listed the foldl/foldr functions on most programming languages, including C++.