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When to use a range based for loop?
It executes a for loop over a range. Used as a more readable equivalent to the traditional for loop operating over a range of values, such as all elements in a container.
Can a range based for loop trigger a deep copy?
This makes it possible to delimit a range by a predicate (e.g. “the iterator points at a null character”). When used with a (non-const) object that has copy-on-write semantics, the range-based for loop may trigger a deep copy by (implicitly) calling the non-const begin () member function.
How to make my custom type to work with range-based?
¹ Note that for (:) loops store any temporary in an auto&& variable, and pass it to you as an lvalue. You cannot detect if you are iterating over a temporary (or other rvalue); such an overload will not be called by a for (:) loop. See [stmt.ranged] 1.2-1.3 from n4527.
Why is std begin not called in range based for loops?
Note that std::begin is not called unless range_expression returns an object of type in namespace std or dependent on same. with the types of __begin and __end have been decoupled. This permits the end iterator to not be the same type as begin.
Used as a more readable equivalent to the traditional for loop operating over a range of values, such as all elements in a container. Note that any init-statement must end with a semicolon ;, which is why it is often described informally as an expression or a declaration followed by a semicolon.
When does a range based for statement end?
A range-based for loop terminates when one of these in statement is executed: a break, return, or goto to a labeled statement outside the range-based for loop. A continue statement in a range-based for loop terminates only the current iteration. Keep in mind these facts about range-based for: Automatically recognizes arrays.
When to use range based for in C + +?
Executes statement repeatedly and sequentially for each element in expression. Use the range-based for statement to construct loops that must execute through a range, which is defined as anything that you can iterate through—for example, std::vector, or any other C++ Standard Library sequence whose range is defined by a begin () and end ().