Defined in the header file template< class Key, class T, class Compare = std::less, class Allocator = std::allocator > class map; (1) namespace pmr { template using map = std::map } (2) (since C++ 17) std::map is an ordered key-value pair container, the key of its elements is unique. Sort keys with comparison function Compare. […]
Tag: stan
An article to understand var, let, const, temporary dead zone
Start the growth journey of Nuggets! This is the Nth day of my participation in the “Nuggets Daily New Plan·February Update Challenge”, click to view the event details This article briefly introduces the basic knowledge. There will be further extensions in the future. Characteristics of variables in js js variables are loosely typed. Variables can […]
Java object instantiation process
If the content is infringing, please contact to delete, if there is something wrong, please criticize and correct. ? Introduction The instantiation process of the object is divided into two parts: the loading and initialization of the class, and the initialization of the object To create an object instance of a class, the class needs […]
[Network Technology] Firewall configuration stand-alone bypass mode
Networking requirements A company deploys an Agile Controller server group on the network, and at the same time deploys a FW at the network egress in a bypass mode, as shown in Figure 1. The requirements are: ?Different user roles can access different network resources (configured on the Agile Controller server). ? After the user […]
Python calculates the distance between two points by latitude and longitude
Python calculates the distance between two points by latitude and longitude There are generally two methods for calculating the distance between two points by latitude and longitude, geodesic distance (assuming the earth is an ellipsoid) and great circle distance (assuming the earth is a sphere). The latter is slightly lower in accuracy than the former, […]
Understanding linux file system/folder name explanation
The linux system is used by many code developers because of its efficient and direct underlying operations. When it comes to linux, everyone’s general impression is the dark terminal command line. Later, the ubuntu version with a visual desktop was developed based on the linux system. Everyone’s experience takes into account the intuitiveness of the […]
Two or three things about Compose: preliminary understanding
What is Compose? Compose is a tool library in the Jetpack series for building native Android interfaces. Jetpack is a series of libraries launched by Google to help developers standardize their code. Simply put, Use code to write UI, that is, declarative UI. The difference between declarative UI and imperative UI is that declarative UI […]
Understand Clang Module and Module Map syntax
Clang Module appeared around 2013, and it appeared to solve the disadvantages of header file inclusion in traditional C-based programming languages. It is also a technology that must be used in modern Apple platform software development. Understanding Clang Module will help us organize code structure, understand Xcode compilation process, optimize compilation speed, and locate compilation […]
Simple instance of I/O multiplexing select/poll/epoll multiplexer
select & poll #include <sys/select.h> /* According to earlier standards */ #include <sys/time.h> #include <sys/types.h> #include <unistd.h> int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout); // Four macros closely combined with select: void FD_CLR(int fd, fd_set *set); int FD_ISSET(int fd, fd_set *set); void FD_SET(int fd, fd_set *set); void FD_ZERO(fd_set *set); select: […]
One article to understand the use of selenium and the installation of various drivers
1. Selenium simulated login Table of Contents Driver Installation Baidu example find node action chain run js get node Switch Frame delay waiting Tab Anti-shield headless mode Previously, requests and other crawling urls are ready-made, and you can request directly, but if you add encrypted parameters, such as token, sign, etc., in addition to js […]