2016年/02月/16日

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编程风格要素

原文

Introduction

Write clearly- don’t be too clever.

清楚地写-但是不要过于聪明

Expression

Say what you mean, simply and directly.

简单，明了地表达你想要表达的

Use library functions.

使用库函数

Avoid temporary variable

避免临时变量

Write clearly – don’t sacrifice clarity for “efficiency”

写清楚-不要为了“效率”牺牲清晰性

Let the machine do the directly work

让计算机去做复杂的事情

Replace repetitive expressions by calls to ca common function

使用通用的函数调用来代替重复的代码

Parenthesize to avoid ambiguity

使用括号来避免歧义

Choose variable names that won’t be confused

选择没有歧义的变量名称

Avoid the Fortran arithmetic IF

避免使用Fortran中的IF

Use the good features of a language; avoid the bad ones

使用语言的好特性，而不是相反

Use the “telephone test” for readability

Control Structure

Follow each decision as closely as possible with its associated action

Don’t stop with your first draft

Program Structure

Modularize

模块化

Make the coupling between modules visible

使模块间的耦合可见

Each module should do one thing well

每个模块只做好一件事

Make sure every module hides something

确保每个模块都隐藏了些东西

Let the data structure the program

让数据将程序变得结构化

Don’t patch bad code – rewrite it

不要修补糟糕的代码-重写吧

Input and Output

Test input for validity and plausibility Make sure input cannot violate the limits of the program Identify bad input; recover if possible Make input easy to prepare and output self-explanatory Make input easy to proofread

Common Blunders

Don’t stop at one bug Watch out for off-by-one errors Avoid multiple exits from loops Make sure your code “does nothing” gracefully Test programs at their boundary values Program defensively 10.0 times 0.1 is hardly ever 1.0

Efficiency and Instrumentation

Make it right before you make it faster Keep it right when you make it faster Make it clear before you make it faster Don’t sacrifice clarity for small gains in “efficiency” Let your compiler do the simple optimizations Don’t strain to re-use code; reorganize instead Keep it simple to make it faster Don’t diddle code to make it faster – find a better algorithm Instrument your programs. Measure before making “efficiency” changes

Documentation and readability

Make sure comments and code agree Don’t just echo the code with comments – make every comment count Don’t comment bad code – rewrite it Use variable names that mean something Format a program to help the reader understand it Document your data layouts Don’t over-comment