为什么 string::find 返回 size_type 而不是迭代器? [英] Why does string::find return size_type and not an iterator?

问题描述

In C++, why does string::find return size_type and not an iterator?

It would make sense because functions like string::replace or string::insert take iterators as input, so you could find some character and immediately pass the returned iterator to replace, etc.

Also, std::find returns an iterator -- why is std::string::find different?

解决方案

The design of the standard library's shiny new string class was already done when Stroustrup introduced the standard committee to the STL. The committee liked the STL and started incorporating it into the standard, thereby adapting much of what they had already agreed on (and probably also delaying the standard for another year or two).

Among other changes, iterators were added to the already finished string class as an after-thought. You can see this by looking at the various string members taking/returning a position – it's a wild mix of indexes and iterators.

It's not always easy to guess why some member functions have only indices-taking versions and some have iterator-taking ones, too. In the case of std::basic_string<>::find(), however, it seems easy: Since std::find() already returns an iterator, std::basic_string<>::find() was left as it was.

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