15, Linux memcpy function

  Function prototype   void *memcpy(void*dest, const void *src, size_t n);   function   Data of N consecutive bytes from SRC to address is copied into a space where destination to address is the starting address.   header file   #include<string.h>   Return value   　　The function returns a pointer to dest.     Explain   　　1.sourceAnd Destin refers to the memory area can not be overlapped, the function returns a pointer to Destin.   　　2.Compared with strcpy, memcpy does not end with’\0′, but it will copy n bytes. 　　memcpyUsed for memory co...

[algorithm] K nearest neighbor algorithm (K-NEAREST NEIGHBOURS (KNN))

KNearest neighbor algorithm (k-nearest neighbours, KNN) algorithm Classifying an element Look at its K nearest neighbor. Among these neighbors, which is more, this element has greater probability than this category.   Use Use KNN to do two basic tasks.Classification and regression：   Classification is grouping.；   Regression is the result of prediction.（For example, a number.   feature extraction Used to determine two elements.Similarity degree   Method Pythagorean formula   Converts a comparable category to a set of coordinates. Pythagorean formula     Regression (regress...

Scan two-dimensional code to become a lower level user.

<div class="header_top bar-nav"> <a class="back-link-icon" href="#pageHome" data-rel="back"></a> <h1 class="page-title-bar">My share code < /h1>< /div><! - common top -->< div class= "wallet-box" >< div style= "width: 100%; height: 11rem; text-align:center" >< img style= "width:100%; height:100%"Src= "/phone/public/images/feixiangpicture.png" />< /div>< div class= "CONT"Style= "display:flex; padding:0 8%; justify-content:space-around;" >< P style= "margin-top: 8%; font-size:.40rem; color:#333 ">"; long cli...

Using gulp and bable to compile ES6 code in real time

This article was first published on my own bloating blog site:Using gulp and bable to compile ES6 code in real time，The blog uses a source of open source, based on thinkjs and vuejs development, welcome you to stroll around.     Problem description> A large and complete Java framework is used in the project development. the framework integrates the front-end and the back-end. the front-end develops JSP pages on the basis of this framework, and the front-end and back-end are not completely separated. Now we have some JS code that uses ES6 syntax, but then we have IE compatibility probl...

MongoDB tutorial (four): MongoDB concept analysis

Summary: 　　No matter what database we learn, we should learn the basic concepts. In mongodb, the basic concepts are documents, collections, databases, and we’ll cover them one by one. 　　The following table will help you understand some concepts in Mongo easier. 　　　　 data base 　　Run database C:\Program Files\MongoDB\Server\4.0\bin&gt first; mongo.exe show dbs —— Displays a list of all databasesUse -- run"use"Command to connect to a specified database.DB -- Implementation"db" The command can display the current database object or collection. 　　  　　N...