Programmer Think

catalogue 1: List II: set 1: List   1.1 overview and characteristics of list set: List collection overview: An ordered set (also known as a sequence), in which the user can accurately control the insertion position of each element in the list. Users can access elements through integer indexes and search for elements in the list.Un ...

Abstract: This paper will describe the interface isolation principle and Dependency Inversion Principle in SOLID principle. This article is shared from the Huawei cloud community "practice the design pattern of GoF 23: SOLID principle (Part 2)", author: yuan Runzi. In< Practice 23 design modes of GoF: SOLID principle (I) >In ...

preface This may be the most convenient and appropriate way to use Icon at present, especially in Vue3. Do you think it is only applicable to Vue3? No, don't be deceived by the title. It supports many mainstream frameworks such as Vue2/Vue3, React, React, Solid and Svelte. Similarly, it also supports Vite, Roullp, Webpack, Nuxt, V ...

The category component is a real Logging object in the Log4Cpp library. We can use the category object to perform various levels of log operations, such as debug, warn, info... And this object can also add various Appenders to distribute log instructions to various appender objects to output to the final destination Relationship between Catego ...

explain field description Adding explain in front of the sql statement to be executed can simulate the execution process of the statement by the optimizer. Example description: explain select * from sys_user; explain will return one or more pieces of data. The meaning of each column is explained below: 1. id execution order. This is a relat ...

1, Foreword In our daily development, we cannot avoid parameter verification. Some people say that the front end will verify in the form? In the back-end, we can directly judge the filtering regardless of how the front-end judges it. Our back-end needs to judge again for security. Because the front end is easy to request. When the test use ...

Server architecture The server system is Centos7 First, we need to know the external architecture of the system General architecture: 1. Domain name - > ECS 2. Domain name - > CDN - > cloud server (OSS) 3. Domain name - > CDN - > ECS + RDS + Redis cache 4. Domain name - > CDN - > Load Balancing - > ECS + RDS (mast ...

This way Meaning: Give you an array a with length n. at the beginning, the color of all positions is 1 and the value is 0 There are three operations at a time: Color l r x: change the color of all positions in [l,r] to X Add c: add c to the values of all positions with color c Q: what is the value of Query i. Solution: This feeling is stil ...

Project properties The following describes the project properties. The container attribute is added to the container, and the item attribute is written on the item, just like the container attribute to ul and the item attribute to li. The following six properties are set on the project: Order: used to determine the order of items. The default ...

Comparison operator= <=> <> != < <= > >= The comparison operator is used to compare the operands on the left and right of the expression. If the comparison result is true, it will return 1, if the comparison result is false, it will return 0, and in other cases, it will return NULL.Comparison operators are often us ...