• Definition and use of C language keyword Union


    Union, Chinese name “union, common body”, is a data structure similar to the structure struct to some extent. The common body (Union) and structure (struct) can also contain many data types and variables. But in Union,   Each member shares a memory space, and the length of a joint variable is equal to the longest […]

  • Analyze the difference between basic data types and reference data types in JS from simple to in-depth


    one   Data classification of JS in a broad sense JS is divided into two data types: 1. Basic data type: number, string, null, Bollean, undefined, symbol (ES6) Whether it can be changed: no (when the basic data type is re assigned, it will point to a new memory address, and the old one will […]

  • Three definition methods of JS function


    How functions are defined Function declaration: it must have a name. It will promote the function. It has been created in the pre parsing stage. It can be called before and after the declaration //Function declaration //Define function name function fn(){ console.log(123); } Function expression: a variable assignment function expression can have no name (anonymous […]

  • [Java from pit entry to abandonment] No 4. Operator


    preface Last articleJava variables and data types are introduced in, so how to run them? In this section, let’s take a look at the operations in java! The main contents of this paper are as follows: Arithmetic operator Relational operator Bitwise Operators Logical operator Assignment Operators Conditional operator Well, don’t say much. Let’s start the […]

  • Design pattern learning 17 (Java implementation) — visitor pattern


    Write in front Take notes on learning design patterns Improve the flexible use of design patterns Learning address https://www.bilibili.com/vide… https://www.bilibili.com/vide… Reference articles http://c.biancheng.net/view/1… Project source codehttps://gitee.com/zhuang-kang/DesignPattern 19. Visitor mode 19.1 definition and characteristics of visitor mode Definition of visitor mode:The operations acting on each element in a data structure are separated and encapsulated into independent […]

  • ES6 feature sorting


    ESMAScript6.0 ES6 compatible IE10+ 、Chrome、Firefox There are two ways to be compatible with ie10: use  babel tool  borwer.js , in  script  Add in label  type=”text/babel” attribute Variables let and Const  let : It is used to define variables and cannot be declared repeatedly  const : It is used to define constants and cannot be declared repeatedly Arrow function Arrow function […]

  • [Jianzhi Java] bullet 1: Based on this summary of java basic knowledge, I got a satisfactory offer


    preface Because the blogger is a graduate of 2021, in order to prepare for the autumn recruitment, he specially summarized the high frequency questions of java basic knowledge interview, and finally found a very satisfactory job. Therefore, give back to you and hope to help you. 0. Basic knowledge 0.1 Java features Easy to learn […]

  • Java basic syntax: operators


    Java operators are classified according to their functions Arithmetic operator:+,-,*,/,%,++,– Assignment Operators := Relational operators:>,=,<=,==,!=,instanceof Logical operators:&&,||,! Bitwise Operators :&,|,^,~,>>,<>> Conditional operator:? : Extended assignment operator:+=,-=,*=,/=,%=,<<=,>>=,&=,^=,|= Operators are classified according to the number of operation data Unary operator:++,–,!,~ Binary operator:+,-,*,/,%,=,>,=,<=,==,!=,instanceof,&&,||,&,|,,>>,<>>,+=,-=,*=,/=,%=,<<=,>>=,&=,=,|= Ternary operator :? : JavaMath classProvides a lot of scientific and engineering calculation methods and […]

  • Piziheng embedded: change iomuxc in i.mxrt1xxx_ GPR register reserved bit may cause system exception


    Hello everyone, I’m a ruffian Heng. I’m a serious technical ruffian. Today, ruffian Heng introduces to youChange iomuxc in i.mxrt1xxx_ GPR register reserved bit may cause system exception。 A very active friend in piziheng’s embedded technology communication group (net name: Wen, piziheng has designated him as the Deputy Group Leader) recently reflected to piziheng a […]

  • Passage 2: using pcntl_ Fock function talking about multi process


    A series of articles: Passage 2: using pcntl_ Fock function talking about multi process Essay 1: using PHP socket to describe the principle of HTTP server introduce pcntlyesphpOfProcess control extension, seePHP manual。 amongpcntl_fork()Is to create a process function. Workman uses this extension ps -ef | grepperhapspstree -apn | grepIt must have been used in general, […]

  • JavaScript ES12 new features preemptive experience


    In the last article, we introduced the nine features of es2020, many of which benefit us a lot.How many new features have you used in es11? Every year, JavaScript will update and add new features and new standards, which will be released in es2020 this year, and es2020 (ES12) is expected to be released in […]

  • Ajax to global variable assignment problem solving example


    Today, I met a problem when I was working on the project. I use ajax. I want to assign a value to a global variable in $. Ajax ({but I can’t assign a value to it. I’ve been struggling for a long time. Later, I checked online and found out that AJAX is an asynchronous […]