Articles
android

C language pointer learning summary

table of Contents Pointer concept Everything is an address Pointer variable Define pointer variables Get data through pointer variables Puzzles about * and & Summary of asterisk* Operation of pointer variables Array pointer 1) Use subscripts 2) Use pointers The puzzle about array pointers String pointer Pointer as function parameter Use arrays as function parameters Pointer as return value Secondary pointer Pointer array Pointer and two-dimensional array The difference between pointer array

... Kaiden
schedule 43 min read
android

Face the underlying bytecode and look at anonymous inner classes and lamdas

Preface In our daily development, we usually encounter anonymous inner classes, and anonymous inner classes hold references to outer classes. What about the bytecode level? This article looks at internal classes and lamdas from the bytecode level 1. Anonymous inner class public class NoNameInnerClass { public static void main (String[] args) { Runnable r = new Runnable() { @Override public void run () { } }; r.run(); } } Copy code We new a runable and then call the run method. Now we compile the

... Olivia
schedule 8 min read
android

Pi Ziheng Embedded: Super easy to use visual PyQt GUI construction tool (Qt Designer)

Hello, everyone, I am the ruffian, a serious ruffian who engages in technology. Today Pi Ziheng introduced to you the PyQt GUI construction tool Qt Designer . Pi Ziheng has opened a blog for several years. He has been focusing on articles on embedded development related topics, occasionally interspersing some introductions of other technologies or tools. Some time ago, I wanted to make a host computer tool NXP- related to NXP MCU startup. MCUBootUtility , I searched and compared several GUI fra

... Faith
schedule 10 min read
android

Hive combat

Hadoop ecosystem: hdfs distributed storage Yarn: If you only save it, it has nothing to do with yarn. hive: Data analysis and analysis can also be based on spark, memory-based, machine learning-based, offline hive-based Use sqoop to export the analyzed results, for example, export to mysql Then springboot access boot: Start the crawler: film_spider-1.0-SNAPSHOT-jar- with-dependencies.ja duplicated code Start hdfs: start-dfs.shCopy code Start flume nohup ./start_flume_to_hdfs.sh & copy code

... Ruby
schedule 13 min read
android

Kotlin scope functions (with, let, also ,apply,run)

The Kotlin standard library contains several functions whose sole purpose is to execute code blocks in the context of an object. When such a function is called on an object and a lambda expression is provided, it forms a temporary scope. In this scope, the object can be accessed without its name. These functions are called Scope function . There are five types:let,run,with,apply as well as also. These functions basically do the same thing: execute a block of code on an object. The difference is

... Evan
schedule 13 min read
coder_life

SpringBoot

Community 1. 1.0 1.1 SpringBoot2.3.x SpringMVC + Mybatis Maven3.6.X + Git MySQL + OSS Thymleaf3.x Wkhtmltopdf + kaptcha Redis + ElasticSearch + Kafka + Caffeine Spring Securtiy + Spring Actuator Ajax + Vue + BootStrap + HTML + jQuery 1.2 SpringBoot pom.xml <!--thymleaf--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <!--web--> <dependency> <groupId>org.spri

... Jason
schedule 37 min read
coder_life

How to use Bluetooth 5.0 to realize remote data collection

1. Introduction to nRF52840 Bluetooth chip Since Nordic launched the nRF52840 blockbuster chip strongly in 2018, Bluetooth 5.0 technology has become popular in the industry, and then Bluetooth 5.0 technology has become the standard feature of flagship mobile phones of major brands. 1. Chip advantage The most powerful advantage of this chip is the low-speed and long-distance mode , and LE_CODED . It is officially claimed that the maximum transmission distance of 300 meters can be achieved. When t

... Summer
schedule 22 min read
coder_life

How do the hardest students in the university computer department study?

This question is often asked by classmates, how do you work hard to find a good job? Can you enter a good company if you study well? fart! The elder senior who was snotted and tearful by the school's education pit came to answer a wave. When I was in college, I won the National Encouragement Scholarship for three consecutive years. I passed CET-6. I thought the soft test was useful. I also took a software designer certificate. I thought CET-4 was useful. I also took a software test engineer cer

... Luke
schedule 22 min read
coder_life

23 design patterns

23 design patterns (Java version) Overview I started my internship as a code farmer in my senior year. Before entering the company, I only knew some simple factory models-such as simple factories (corresponding to "complex" factories), singleton mode, and agency mode. But these are only general understandings, but they can't be described very well. During the first week of the internship, in the process of reading the source code of the project. I found that there are design patterns that I have

... Cooper
schedule 72 min read
coder_life

Java knowledge summary (1)

1 Overview 1.1 Overview of the overall content of java 1.2 The relationship between JDK, JRE, and JVM 1.3 Comment: Comment Category : Single line comment:// Multi-line comments:/* */ Documentation notes:/** */ Note : Multi-line comments cannot be nested 2. Basic grammar 2.1 Keywords and identifiers 2.1.1 Use of keywords Definition: A string (word) given a special meaning by the Java language and used as a special purpose Feature: All letters in keywords are lowercase Specific keywords: 2.1.2 Use

... Emmett
schedule 20 min read
dev_tools

Computer network knowledge frequently asked in front-end interviews

This article has participated in the Haowen Convening Order activity, click to view: Back-end, big front-end dual track submissions, 20,000 yuan prize pool waiting for your challenge! OSI and TCP/IP model What happened to the address Hypothetical input www.baidu.com The browser resolves the domain name. When the client and the server exchange data, the domain name cannot be recognized, and the unused IP address is converted through DNS resolution of the domain name Look up whether there is a map

... Hannah
schedule 29 min read
dev_tools

(Essence) The use of microservice WCF on August 17, 2020

Compared with webservice, WCF features: Support different protocols: http tcp IPC MSMQ p2p Support different hosts: website console winform WindowsService Duplex protocol (can be sent while receiving), Let's talk about the first method of using WCF: One: Configure the following code in the routing of the asp.net website public class RouteConfig { public static void RegisterRoutes ( RouteCollection routes ) { routes.IgnoreRoute( "{resource}.axd/{*pathInfo}" ); routes.IgnoreRoute( "Remote/{*pathI

... Luke
schedule 7 min read
dev_tools

Differences between Vue and React

Preface Both Vue and React are currently one of the most popular and ecologically best front-end frameworks. The framework itself has no distinction between good and bad, only the difference is applicable, and choosing the technology that meets our own business scenarios and team foundation is our main purpose. text Design ideas vue Vue's official website says that it is a progressive framework that uses a bottom-up incremental development design. Here we need to clarify a concept, what is a pro

... Ella
schedule 21 min read
dev_tools

Front-end algorithm problem

0. Xiaohao Algorithm // Bubble const array = [ 23 , 3 , 12 , 44 , 42 , 344 ]; function bubbleSort ( arr ) { const len = arr.length; for ( let i = 0 ; i <len- 1 ; i++) { for ( let j = 0 ; j <len-i- 1 ; j++) { if (arr[j]> arr[j + 1 ]) { const temp = arr[j +1 ]; arr[j + 1 ] = arr[j]; arr[j] = temp; } } } return arr; } bubbleSort(array); // select function selectSort ( arr ) { const len = arr.length; let minIndex; let temp; for ( let i = 0 ; i <len- 1 ; i++) { minIndex = i; for ( let j =

... Miles
schedule 25 min read
dev_tools

Spring annotation-driven development (1)-component registration

There are the following methods to register components in the container Package scanning + component annotation annotation (@Controller/@Service/@Repository/@Component) [class written by yourself] @Bean[Components in the imported third-party package] @Import[Quickly import a component into the container] @Import (the component to be imported into the container); this component will be automatically registered in the container, and the id is the full class name by default ImportSelector: returns

... Noah
schedule 8 min read
programming

Node.js learning diary (7): Connect framework and some commonly used middleware

eg. A simple image hosting website Service-Terminal ar fs = require ( 'fs' ) var http = require ( 'http' ) var qs = require ( 'querystring' ) var server=http.createServer( function ( req,res ) { function serve ( path,type ) { res.writeHead( 200 ,type) fs.createReadStream(path).pipe(res) } if (req.method== "GET" &&req.url== "/" ){ serve(__dirname+ ' /index.html' , 'text/html' ) } else if (req.method== "GET" &&req.url.substr( 0 , 7 )== "/images" &&req.url.substr(- 4 )== ".j

... Harrison
schedule 8 min read
programming

BATJTMD, recruiting from big factories, how do you deal with Java programmers?

Author: Small Fu brother blog: bugstack.cn Precipitate, share, grow, so that you and others can gain something! I. Introduction To what extent can I learn Java to find a job? Recently, I always see problems like this, and some friends who have been working for about 3 years ask Brother Fu how to enter a big factory. In fact, you say how much you can learn Java to find a job, mainly depends on which city you want to find, what kind of company you are looking for, and what kind of salary you are l

... Makayla
schedule 31 min read
programming

C++ Builder API functions

C++ Builder API functions 1. API network functions WNetAddConnection Creates a permanent connection to the same network resource WNetAddConnection2 Creates a connection to the same network resource WNetAddConnection3 Creates a connection to the same network resource WNetCancelConnection Ends a network connection WNetCancelConnection2 Ends a network connection WNetCloseEnum Ends an enumeration operation WNetConnectionDialog starts a standard dialog box Establish a connection with a network resour

... Harrison
schedule 47 min read
programming

[EMG signal] pulse signal processing system based on matlab GUI [including Matlab source code 1062 period]

1. Introduction EMG, the application of electronic equipment to record the electrical activity of muscles at rest or contraction, and the application of electrical stimulation to check nerve and muscle excitation and conduction functions. The English abbreviation is EMG. Through this examination, the functional status of peripheral nerves, neurons, neuromuscular junctions and muscles can be determined. By measuring the time limit and amplitude of motor unit potential, whether there is spontaneou

... Daisy
schedule 10 min read
programming

Pointers are the essence of C

"C Language Advanced Topics Part 3-4.3. Pointers are the essence of C" Course features: explain the profound things in a simple way, learnable, speak with examples The first part, chapter table of contents 4.3.1. What exactly is a pointer? 4.3.2. Understanding of some symbols brought by pointers 4.3.3. Wild pointer problems 4.3.4 . const keyword and pointers 4.3.5. Learn more about arrays 4.3.6. The natural relationship between pointers and arrays 4.3.7 Pointer and coercive type conversion 4.3.8

... Jackson
schedule 40 min read
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