August 2021
Intermediate to advanced
450 pages
9h 36m
Chinese
Content preview from C++程序设计：原理与实践（基础篇）（原书第2版）
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
14.2.3 resize
实现了reserve（）后，再为vector实现reszie（）就很简单了。我们只需处理以下几种情况：
·新的大小大于已分配的空间。
·新的大小大于当前大小，但小于或等于已分配空间。
·新的大小等于当前大小。
·新的大小小于当前大小。
下面的代码展示了resize（）的实现：
我们用reserve（）处理困难的内存空间管理问题。代码中的循环将初始化新的元素（如果有的话）。
在本例中，我们没有显式地处理每一种情况，但你可以验证：在上述代码中，每一种情况均被正确地处理了。
试一试
如果我们需要证明上述resize（）是否正确，那么需要考虑（并测试）哪些情况？当newsize==0时会怎样？当newsize==-77呢？
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.