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）
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7.6.3 代码布局
重新检查一下计算器程序，看看其中是否有“丑陋”的代码，我们发现：
在加入对'q'、'；'和'%'的处理之前，这段代码还不算太坏，但现在变得有些混乱。代码的可读性越差，其中的错误就越难以发现。而这段代码中确实隐藏着一个潜在的bug！我们修改一下代码，令每行代码只对应switch语句的一种情况，并加入适当的注释来帮助代码理解。修改后的Token_stream的get（）函数如下所示：
我们当然可以把对每个数字的处理也放在不同的行，但是那样似乎并不能使代码更加清晰，而且导致不能在一屏上显示get（）函数的所有代码。理想情况是，每个函数的代码都能全部显示在屏幕的可视区域上——在屏幕之外我们无法看到的代码是最有可能隐藏bug的地方。因此，代码布局是非常重要的。
另外一个值得注意的地方是，我们在程序中用符号常量quit替代了字符'q'。这不但提高了程序的可读性，而且保证我们的编程错误会被编译器捕获——如果我们为quit操作选择的单词与其他单词冲突，将会产生一个编译时错误。
在代码清理阶段，我们有可能意外地引入一些错误。因此，在代码清理之后一定要测试代码的正确性。最好是每做一点改动就测试一次，以便发现错误时你能记起来是做了什么样的改动导致的这个错误。记住：及早测试，经常测试。 ...
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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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