Programmer Think

preface In this chapter, we will learn two patterns of behavioral patterns, strategy pattern and Template Pattern. Strategy mode brief introduction A Strategy Pattern belongs to the behavior pattern of an object. Its purpose is to encapsulate each algorithm into an independent class with a common interface for a group of algorithms, so t ...

When upgrading the image viewer some time ago, there was no good transition mode when opening the image viewer. A big man recommended the latest Material Motion animation for Android to me. Although it was not arranged for our App in the end, it provided me with an opportunity to learn Material Motion animation. Recommended learning materials ...

Template method design pattern is a behavioral design pattern. This pattern is commonly used to define a template or algorithm model for a specific operation. Take OTP (One Time Password) as an example. There are two common one-time passwords: SMS password (SMS OTP) or email password (Email OTP). However, the processing steps of both SMS passw ...

Singleton pattern is probably the most well-known design pattern. It is also a kind of creative mode. We will use this design pattern when only one instance of a struct is allowed. The only instance of this struct is called a singleton object. Here are some scenarios where you need to create a singleton object: Database instance: generally, in ...

Weather forecast demand Specific requirements are as follows: ● 1) the weather station can publish the daily measured temperature, humidity, air pressure, etc. in the form of announcement (for example, to its own website or a third party) ● 2) it is necessary to design an open API so that other third parties can access the weather station ...

First, can a stack be pressed with a pointer? Of course, write a simple stack here When it comes to pointers, you may think of strings. We can pass in the following types string str; The simplest input, thanks to the powerful string class provided by C + +, we can easily complete this operation char str[size]; C-style string, but it may no ...

Problem scenario The new mobile phone is too expensive. Users want to buy it, but they suffer from limited funds. They go to the second-hand market and find that the price is much cheaper than the positive price in the market. They buy it immediately. Unexpectedly, the mobile phone has been used by the root. What can we do? Buying a mobile pho ...

The singleton design pattern is very simple to understand. A class can only create one object (or instance), and this class is a singleton class. This design pattern is called singleton pattern.Usage scenarioHandling resource access conflictsIn the following example, if each class creates a Logger instance, the log content may be overwritten.pu ...

Visitor mode 1 Definition Encapsulates some operations that act on each element in a data structure. It can define new operations that act on these elements without changing the data structure. 2 Structure The visitor pattern contains the following main roles: Abstract visitor role: defines the behavior of accessing each element. Its param ...

Template mode: it belongs to behavioral design mode. It is one of the more commonly used and simpler design modes. Although you may not know how to write template mode, you may have used it long ago. Let's start with a definition: Template mode: define the algorithm skeleton in an operation, and delay some steps of the algorithm to the subclass ...