The front end creates a local wallet and implements signature transfer (BSC, Polygon, ETH)

Article directory 1. Project preparation 2. Wallet-related concepts 3. Randomly create a wallet 4. Import the wallet according to the mnemonic 5. Import wallet according to keystore 6. Signature transfer 1. Project preparation Install ether.js npm install –save ethers Three ways to introduce ether.js: es3: var ethers = require(‘ethers’); es5/es6 const ethers = require(‘ethers’); javascript/typescript-es6 […]

pyqt5 makes a simple drawing board

Foreword In the last blog Pyqt5 and opencv change the background color of the photo – Programmer Sought Used to draw the board, but not set the brush. So on this basis, operate on the brush. draw better Text First look at the operation after running Operation first open a picture For example, this After […]

Tomcat important parameter tuning

One. 3 parameters to get the concurrent configuration As a web container that can undertake high concurrent Internet requests, the first to bear the brunt is of course the impact of massive requests. Fortunately, Tomcat supports NIO, and we can adjust the number of threads and concurrency configuration to make it show the best performance. […]

C++ simulation implementation string

Article directory foreword 1. Related header files included 2. Construction and destruction 1. Constructor 2. Copy construction 1. Traditional writing 2. Modern writing 3. Assignment operator overloading 1. Traditional writing 2. Modern writing 4. Destructor Three, iterator Four, modify 1.push_back (insert a character at the end) 2.append (insert a string at the end) 3. Operator […]

MySQL database implements master-master synchronization

Foreword MySQL master-master synchronization actually promotes slave database to master database on the basis of master-slave synchronization, so that they can read and write databases with each other, and slave database becomes master Database; the process of master-slave mutual authorization connection, reading the binlog log of the other party and updating it to the local […]

Front-end direct transmission of cos using temporary key & implementing node to obtain temporary key interface

Background The originally used cos is the node interface called, but because the gateway of the company’s node project limits the size of the uploaded file, then the front end directly uploads the cos (mainly to do it yourself); but! It is very unsafe to use a fixed key to directly upload cos from the […]

[NOIP2007 Improvement Group] String Expansion

Description of topic In the question of “reading program writing results” in the popularization group of the preliminary round, we gave an example of string expansion: if the input string contains a string similar to d-h or 4 -8 string, we regard it as a shorthand. When outputting, replace the minus sign with a continuously […]

Make a simple HTML static web page (HTML+CSS)

Excellent column recommendationGet contact at the end of the article About the author: A technical blogger who loves to turn logical thinking into code Author’s homepage: [Homepage–? Get more high-quality source code] Web front-end major homework: 【Practice cases of high-quality project projects (1000 sets) 】 Programmer’s interesting confession method: 【HTML Tanabata Valentine’s Day Confession Web […]