• [react] this in react


    class App extends React.Component{ constructor(props) { super(props); //To make this point to the current class // this.handleClick = this.handleClick.bind(this); } //Test function handler() { Console.log (` handler is called, this points to: ‘, this)); } render(){ return( <div> <h1>hello World</h1> < label htmlfor =’btn ‘> click this in the print function handler to point to […]

  • [front end ramble] slapping all kinds of concepts in Git


    0x000 Guide speakgitThere are a lot of articles, but most of them are a routine. They talk about concepts and commands. Too many concepts and commands always make people feel confused. What they say is very right, but they don’t seem to be able to explain it thoroughly. They don’t have the feeling of enlightening. […]

  • Null pointer and void pointer in C language


    Null pointer and void pointer in C languageShuimanting520 2016-05-10 07:12:12 18926 collection 30Category column: C / C + + article tag: C + + pointer void nullcopyrightNull pointer nullIn C language, if a pointer does not point to any data, we call it a null pointer, which is represented by null. For example: int *p […]

  • What is the structure of redis key value pair?


    What is the structure of redis key value pair? A global hash table (array) is composed of multiple hash buckets (elements on the array, including entry elements) For example, key name: AAA, key value: BBBThrough hash (AAA), get array subscript 6, then hash bucket 6. The entry element in hash bucket 6 containsKey andValue pointer,Key […]

  • ThreadX — message queue of IPC application


    Author:zzssdd2 E-mail:[email protected] 1、 Application Introduction Message queuingIt is a common way of data communication in RTOS, which is often used for data transmission between tasks or between interrupts and tasks. In bare metal systems, we usually use global variables to transfer data. For example, after an event occurs, we change the data and set flags […]

  • Learning notes of C + +


    Quotation: it is a kind of rhetorical device, which refers to the words of famous people, or the things, things, poems, allusions, fables, idioms, proverbs, proverbs, etc. of famous people to support the author’s position, so as to prove and strengthen his theory and enrich the content of the article [1].–Wikipedia In C + +, […]

  • C language pointer


    (1) Pointer knowledge forerunner 1. Memory space and memory address int num=100;Data in computer is stored in memory, so the essence of reading and writing data is actually reading and writing memory. At present, the only way to read and write memory is through variable name, which is called “direct access” memory. In a computer, […]

  • Simple simulation of call, apply and bind methods in JavaScript


    catalogue Introduction Implicit loss Hard binding Realization and principle analysis Overall implementation (pure version / no comments) Write at the end Introduction After reading the introduction and in-depth chapter about this in the JavaScript you don’t know Volume I, the direction of thisI use this article to summarize. Then I wonder if I can use […]

  • Redis QuickList source code analysis


    1、 Introduction to QuickList Redis list is a simple list of strings, sorted by insertion order. You can add an element to the top (left) or bottom (right) of the list. A list can contain at most   two32-1 element (4294967295, more than 4 billion elements per list). QuickList is the internal data structure that […]

  • C: Pointer


    Pointer 1. Pointer and array Array: name []; The array name is essentially equivalent to the first address of the array, and name [] is equivalent to the value of the address Pointer: * P, declare a pointer to (type) P = name, P is an address, pointing to the first address of name Usage: […]

  • Leetcode 680. Verify palindrome string II | Python


    680. Verify palindrome string II Title Source: https://leetcode-cn.com/problems/valid-palindrome-ii subject Given a non empty string s, at most one character is deleted. Determine whether it can be a palindrome string. Example 1: Input: “ABA” Output: true Example 2: Input: “ABCA” Output: true Explanation: you can delete the C character. be careful: The string contains only lowercase […]

  • Call, apply and bind in JS


    Call and apply call 1. Usage:foo.call(obj, arg1, arg2, …) -> It is mainly used to change the direction of this; function foo(year, place) {   console.log(this.name+” is “+year+” born from “+place); } window.name = ‘syz’; const obj = {   name: ‘syc’ } foo(1995, ‘china’); // syz is 1995 born from china foo.call(obj, 1995, ‘china’); // syc is 1995 born from china First of all, we need to know that this in each function is bound when it is called, and where this points to depends entirely on […]