C++核心准则​SL.io.3：优先使用iostream进行I / O

SL.io.3: Prefer iostreams for I/O

SL.io.3：优先使用iostream进行I / O

Reason（原因）

iostreams are safe, flexible, and extensible.

iostream安全，灵活且可扩展。

Example（示例）

// write a complex number:
complex<double> z{ 3, 4 };
cout << z << '\n';

complex is a user-defined type and its I/O is defined without modifying the iostream library.

complex是用户定义的类型，无需修改iostream库即可定义其I / O。

Example（示例）

// read a file of complex numbers:
for (complex<double> z; cin >> z; )
    v.push_back(z);

Exception（例外）

??? performance ???

??? 性能???

Discussion: iostreams vs. the printf() family

讨论：iostreams与printf（）函数群

It is often (and often correctly) pointed out that the printf() family has two advantages compared to iostreams: flexibility of formatting and performance. This has to be weighed against iostreams advantages of extensibility to handle user-defined types, resilient against security violations, implicit memory management, and locale handling.

人们经常（经常正确地）指出，与iostream相比，printf（）函数群具有两个优点：格式化的灵活性和性能。必须权衡iostream的优势：处理用户定义的类型时的可扩展性，可抵御安全性违规，隐式内存管理和区域设置处理。

If you need I/O performance, you can almost always do better than printf().

如果需要保证I / O性能，iostream几乎可以总是比printf（）更好。

gets(), scanf() using %s, and printf() using %s are security hazards (vulnerable to buffer overflow and generally error-prone). C11 defines some "optional extensions" that do extra checking of their arguments. If present in your C library, gets_s(), scanf_s(), and printf_s() might be safer alternatives, but they are still not type safe.

使用％s的gets（），scanf（）和使用％s的printf（）都有安全隐患（很容易造成缓冲区溢出并且通常容易出错）。C11定义了一些“可选扩展”，对它们的参数进行了额外的检查。如果是在使用C语言库，gets_s（），scanf_s（）和printf_s（）可能是更安全的选项，但它们仍然不是类型安全的。

Enforcement（实施建议）

Optionally flag <cstdio> and <stdio.h>.

（可选）标记<cstdio>和<stdio.h>。

原文链接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#slio3-prefer-iostreams-for-io