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So far, you can create a Pygame window and render a ball that will fly on the screen. The next step is to make some bats that users can control. This may be much simpler than a ball because it doesn't require physical elements (unless your user controls the movement of objects more complex than up and down, in which case you need more physical ...

Immutable object Immutable object: after an object is created, its content cannot be changed, There is one exception: assign a value to this object in the form of an assignment operator (in the form of member copy), That is, copy other objects to the current object. In this case, its content can be changed! Immutable objects have many adv ...

mybatis advanced learning Content introduction Dynamic sqlMulti table query in mybatisNested query in mybatisLazy loading (delayed loading)cache A mapping file - dynamic sql When we want to execute different sql statements according to different conditions, we need to use dynamic sql. For example: multi condition query, password modificati ...

Chapter II basic knowledge required for interview 1. Array Sword finger Offer 03 Duplicate number in array Find duplicate numbers in the array. All numbers in an array num of length n are in the range of 0 ~ n-1. Some numbers in the array are repeated, but I don't know how many numbers are repeated, or how many times each number is repeated. ...

Usage of Java inner classes and anonymous inner classes 1, Internal class: Why are there inner classes? 1. If there is no method with the same name in the internal class, you can directly call the method of the external class. 2. If the internal class has a method with the same name, it must be called in the format of "OuterClass.this.Met ...

preface Previously, a gitlab server was built on Alibaba cloud student computers. Because gitlab already exists on the host and the environment has been messed up, it is not easy to install gitlab directly, so we have to run it in the docker container. It is very convenient for gitlab to deploy docker container. You can use it by switching th ...

1. Include header file #include <sys/types.h> #include <sys/socket.h> #include <sys/un.h> #include <arpa/inet.h> #include <unistd.h> #include <string.h> #include <time.h> #include <stdlib.h> #include <stdbool.h> #include <net/if.h> 2. Set src and dest, and define a global socket at ...

Before learning html dom, you must have HTML，CSS and Javascript Knowledge reserve. 1. Interpret DOM, HTML DOM, and XML DOM 1. What is DOM? Here DOM, the full name is short for Document Object Model. DOM is the standard of the W3C (World Wide Web Consortium). DOM defines standards for accessing HTML and XML documents. 2. What is an XML ...

Special symbols and characters 0x01 match multiple regular expressions| Pipe symbol, select one of multiple modes, regular mode at|home >>> str = re.match("at|home","home") >>> str.group() 'home' >>> str = re.match("at|home","at qaq") >>> str.group() 'at' 0x02 matches any single character A period o ...

1. What is freemaker and what is its main function? freemarker is a template engine, which is a general tool based on templates and data to be changed and used to generate output text (HTML web pages, e-mail, configuration files, source code, etc.). This is the official explanation. My personal understanding is that freemaker is a template engi ...