Programmer Think

The idea of realizing address book is as follows: 1. When the program runs, the user should first see the Menu bar options and make a choice corresponding to the options given in the Menu bar. Here, we simply design a Menu() function to let the user see the optional items; 2. The user's optional range should be 1 ~ 7. In order to avoid th ...

ConcurrentHashMap is a multi-threaded version of HashMap. HashMap will have various problems during concurrent operation, such as dead circulation, data coverage and so on. These problems can be perfectly solved by using ConcurrentHashMap. Here's the problem. How does ConcurrentHashMap ensure thread safety? How is its bottom layer realized? Nex ...

Java foundation 05 method A Java method is a collection of statements that together perform a function. Method is an ordered combination of steps to solve a class of problemsMethod is contained in a class or objectMethods are created in the program and referenced elsewherePrinciple of design method: the original intention of method is fun ...

The following are my notes on watching the Java learning video of shangsilicon valley Why generics Generic can be understood as a tag, which is jdk5 0 new features Analogy: there are labels on the outside of each drawer in a traditional Chinese medicine store, and only the drugs represented by the labels can be stored in the drawer. We can ...

Use C language to realize a simple minesweeping game! [game requirements] [mine sweeping game]: Layout Thunder - 10Minesweeping: enter coordinates It was thunder - > killed! game over! Not Thunder - > tell you how many thunder there are on the eight coordinates around this coordinate. Until all the non mine positions are found ...

abnormal 1. What is an exception? Broadly speaking, exception refers to all abnormal conditions, including Error Exception In java, abnormal conditions are divided into: Error: refers to problems that cannot be solved by the program, such as insufficient memory, heap overflow and JVM crash Exception (narrow sense): for example: stack ov ...

1, Classes and objects 1. Class and object concepts Everything is an object with attributes and methods. Objects with the same properties and methods (the same properties) can be abstracted as classes. Properties and objects in a class are collectively referred to as members Attributes are also called member attributes, and member variab ...

tslearn is a Python package that provides machine learning tools for analyzing time series. This package builds on (and therefore relies on) the scikit learn, numpy, and scipy libraries. 1 time series data format Use to_time_series function to generate time series data from tslearn.utils import to_time_series time_series_lst=[1,3,5,7,9] ti ...

The essence of annotation When talking about the essence of annotation, the simplest way is to decompile. See the essence. The code is as follows: import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; @Retention(RetentionPolicy.RUNTIME) public @interface Foo{ String[] value(); boolean bar(); } Use the ...

catalogue 1. Why does dynamic memory management exist 2. Introduction to dynamic memory function 2.1 malloc 2.2 calloc  2.3 realloc 3 common errors in dynamic memory allocation i 3.1 dereference of NULL pointer 3.2 cross border access to dynamic development space 3.3 free release for non dynamic development memory 3.4} use free to r ...