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This article mainly introduces "how C++ expresses ideas directly in code". In daily operation, I believe many people have doubts about how C++ expresses ideas directly in code. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts about "how C++ expresses ideas directly in code." Next, please follow the editor to study!

P.1: Express ideas directly in code (express ideas directly in code) Reason (reason)

Compilers don't read comments (or design documents), and programmers don't (consistently). What is expressed through the code is defined by syntax and can (theoretically) be checked by compilers and other tools.

Exampleclass Date {public: Month month () const; / / do int month (); / / don't / /...}

The first month declaration makes it clear that you return the Montrh and do not modify the state of the Data object. The second statement requires the reader to guess and leaves more possibilities for unknown errors.

Example, bad (counterexample)

This loop is a restricted form of std::find:

Loops are only a limited form of std::find.

Void f (vector& v) {string val; cin > > val; / /... Int index =-1; / / bad, plus should use gsl::index / / is not good, plus gsl::index for should be used (int I = 0; I

< v.size(); ++i) { if (v[i] == val) { index = i; break; } } // ...}Example, good（正确示例） A much clearer expression of intent would be: 意图的最明确表达是下面这个样子： void f(vector& v){ string val; cin >

> val; / /... Auto p = find (begin (v), end (v), val); / / better, better / /...}

Well-designed libraries express intentions better than using language features directly (what to do rather than just how to do it).

C++ programmers should understand the basics of the standard library and use it properly. Any programmer should understand the basic library being used by the project and be able to use it appropriately. Any programmer who uses this guide should know the rule support library and use it properly.

Example (example) change_speed (double s); / / bad: what does s signify? / / Bad: what does s mean? / /. Change_speed (2.3)

It is better to clarify the meaning of double (is it a new speed or a change relative to speed? ) and units.

Change_speed (Speed s); / / better: the meaning of s is specified / / better: define the meaning of s /... change_speed (2.3); / / error: no unit error: no unit change_speed (23m / 10s); / / meters per second meters per second

We can accept an undecorated string value as the amount of variation, but this can easily lead to errors. If we want both absolute speed and speed variation, we need to define a Delta type.

Translator's note: the writing of change_speed (23m/10s) is a bit rare, which we will explain in tomorrow's article.

Enforcement (implementation recommendations)

Very hard in general. Generally speaking, it is difficult to implement.

Use const consistently (check if member functions modify their object; check if functions modify arguments passed by pointer or reference)

Stick to const (check whether the member function modifies the object; check whether the function modifies the parameters passed by pointers or references)

Flag uses of casts (casts neuter the type system)

Pay attention to the use of type conversion (type conversion will make the type system ineffective)

Detect code that mimics the standard library (hard)

Found code that mimics the standard library (difficulty)

At this point, the study of "how C++ expresses ideas directly in code" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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