Fix copy_n to increment only n-1 times for an input iterator. This works much better with std::istream_iterator<int>(std::cin). Credit: Matan Nassau.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@126581 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/algorithm b/include/algorithm
index d91c57c..4909221 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -1559,8 +1559,17 @@
>::type
copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
{
- for (; __n > 0; --__n, ++__first, ++__result)
+ if (__n > 0)
+ {
*__result = *__first;
+ ++__result;
+ for (--__n; __n > 0; --__n)
+ {
+ ++__first;
+ *__result = *__first;
+ ++__result;
+ }
+ }
return __result;
}