c++11 standard template (STL) std::map (3)

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. […]

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 […]

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, […]

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 […]