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Mind map closure Before understanding closures, let's learn about the memory release of the parent scope and stack. Concept of parent scope Where is the parent scope of a function created and who is the parent scope var a = 10 function foo(){ console.log(a) } function sum() { var a = 20 foo() } sum() /* output 10 / ...

I think everyone must have read the explanations and sermons of various "strategic models" more or less. This article is to "clarify" the strategic models and try to answer the following questions: 1. How does the policy pattern optimize the business logic code structure? 2. How can you kill a chicken with an ox knife? Jus ...

First, take a look at a classic code and count its execution time: // test_predict.cc #include <algorithm> #include <ctime> #include <iostream> int main() { const unsigned ARRAY_SIZE = 50000; int data[ARRAY_SIZE]; const unsigned DATA_STRIDE = 256; for (unsigned c = 0; c < ARRAY_SIZE; ++c) data[c] = std::r ...

javascript article 1, Data type There are several types of JavaScript Basic data types: undefined, null, boolean, number, string, symbol (new data type of ES6)Reference data types: object, array, function (collectively referred to as object) Data type detection typeof ， for basic data types, the correct type can be displayed except ， nul ...

A good memory is better than a bad pen. If you can write down something, you can write it down. If you have time to take it out and have a look, you will find a different feeling. catalogue preface Zero, class diagram and flow chart 1, Main process 1: get connection process 2, Main process 2: initializing pool objects 3, Process 1.1: obta ...

Stopwatch is interpreted as a timer, also known as stopwatch and stop watch. Obviously, it records time. How to use Stopwatch stopwatch = Stopwatch.createStarted(); doSomething(); stopwatch.stop(); // optional long millis = stopwatch.elapsed(MILLISECONDS); // formatted string like "12.3 ms"} log.info("time: " + stopwatch); Android ...

CSS realizes various methods of horizontal, vertical and horizontal centering of box model CSS method for realizing horizontal centering of box model Global style .parent { color: #FFFFFF; height: 200px; width: 200px; margin: 0 auto; background-color: #000000; } .child { width: 50px; height: 50px; background-color: #26f12d; } First ...

what: What is unit testing how: How to conduct unit tests why: Why unit testing 1, What is unit testing 1. Unit test Unit can be simply understood as a method, so unit testing is testing for methods 2. The position of unit test in the test Generally speaking, small tests are used to ensure code quality, and medium and large tests are us ...

Author Tao FuSource: Ali technical official accountintroduction:This paper prefers practice rather than methodology. The writing method of SpringBoot unit test mentioned in this paper is not an official solution, but a writing method that the author thinks is more convenient and efficient. Each team and even each developer in the team may have ...

DataBinding is a framework officially released by Google. As its name suggests, it is data binding. It is an implementation of MVVM mode on Android. It is used to reduce the coupling between layout and logic and make the code logic clearer. Compared with MVP, MVVM actually replaces the Presenter layer with the ViewModel layer. DataBinding can o ...