April 2018
Intermediate to advanced
303 pages
4h 54m
Chinese
Content preview from Effective Modern C++（中文版）
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113
第
4
章
智能指针
诗人和作曲家往往对爱情情有独钟，有时又对计数偏爱有加，偶然也会把两者兼收并
蓄。伊丽莎白
·
巴雷特
·
勃朗宁（
Elizabeth Barrett Browning
）有诗云，“何以爱汝，待
我细数”（
How do I love thee? Let me count the ways
），保罗
·
西蒙（
Paul Simon
）
亦有绝唱，“逃离爱娇娃，必有五十法”（
There must be 50 ways to leave your
lover
），受此启发，我们也来把对于裸指针实在爱不起来的理由一一列举。
1.
裸指针在声明中并没有指出，裸指针指涉到的是单个对象还是一个数组。
2.
裸指针在声明中也没有提示在使用完指涉的对象以后，是否需要析构它。换言之，
你从声明中看不出来指针是否拥有（
own
）其指涉的对象。
3.
即使知道需要析构指针所指涉的对象，也不可能知道如何析构才是适当的。是应
该使用
delete
运算符呢，还是别有它途（例如，可能需要把指针传入一个专门的、
用于析构的函数）？
4.
即使知道了应该使用
delete
运算符，参见理由
1
，还是会发生到底应该用单个对
象形式（“
delete
”）还是数组形式（“
delete[]
”）的疑问。一旦用错，就会导
致未定义行为。
5.
即启用够确信，指针拥有其指涉的对象，并且也确知应该如何析构，要保证析构
在所有代码路径上都仅执行一次（包括那些异常导致的路径）仍然困难重重。只
要少在一条路径上执行，就会导致资源泄漏。而如果析构在一条路径上执行了多
于一次，则会导致未定义行为。 ...
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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.
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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.