SEARCH KEYWORD -- Difference


  Do we need other languages other than C and C++?

There were hundreds of or thousands of programming languages created since the invention of computer. All these languages have the same target which is to make the computer do what we want it do. So we may find that many languages have the same functions, i.e, one task can be completed by one language can be completed by another language as well. Now we may wonder why we need so many different languages. Can we just have C or C++ since they provide the best performance we need. The answer obviou...

   programming language,C,Erlang     2014-06-14 19:39:40

  <=> operator in MySQL

Have you ever seen "<=>" in a SQL query while using MySQL? Does it mean less and equals to and greater than? Actually if you consider it as the union of <= and =>, great, you are close to it. This is one form of equal operator in MySQL, it has the similar meaning to the = operator with some subtle difference. According to MySQL documentation, <=> is NULL-safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operand...

   MySQL,NULL safe,<=>     2014-03-24 06:23:22

  Difference between ConcurrentHashMap and Hashtable

Both ConcurrentHashMap and Hashtable are Collection classes for storing key value pairs and they both provide fast element search with a supplied key. They have much in common. However, we will not discuss the similarities between them here, instead we will focus on the differences between them. ConcurrentHashMap and Hashtable are both thread safe. But the mechanism for thread safe is different between them. Hashtable is synchronized, it utilizes the synchronization mechanism; while ConcurrentHa...

   ConcurrentHashMap,Hashtable     2013-11-18 08:06:54

  Difference between localhost and 127.0.0.1

Lots of people would think what the address 127.0.0.1 is when first seeing this address. In fact, 127.0.0.1 is a loopback address which refers to the local machine. It is generally used for local testing. When typing ping 127.0.0.1 on local command console, it will send network packets to local IP/TCP layer to test whether IP/TCP works properly or not.  To those who are used to use localhost, it is actually mapped to 127.0.0.1 by default. There are hosts files in the system which store this...

   LINUX,NETWORK,LOCALHOST,127.0.0.1,LOCALHOST VS 127.0.0.1     2018-09-29 22:11:12

  Break down defer statements in GoLang

Basic Concepts What are the characteristics of the deferred statement defer in Go language? When is it usually used? The deferred statement(defer statement) in Go language has the following characteristics: Deferred Execution: Deferred statements are executed before the function containing them exits, regardless of whether the function returns normally or encounters an exception. Last In, First Out (LIFO): If there are multiple deferred statements, they are executed in the order of last in, f...

   DEFER,GOLANG     2024-02-10 21:56:10

  CSS DIV position analysis

When using CSS to set the position of DIV, we may often get confused with the 4 position properties : static, relative, absolute and fixed. If we don't understand them correctly, we may often get unexpected result. Here we make some analysis to them.The definitions of these 4 properties:static : The default position property. It has no position actually. The element will appear where it should be (top, bottom, left, right or z-index has no use here)relative : This one will position relati...

   CSS, DIV,position,relative,absolute     2013-01-29 03:23:57

  Understanding Slice Behavior in Go

In Go, understanding how slices behave when passed to functions is crucial for writing efficient and bug-free code. This behavior is often a source of confusion for many developers, especially those new to the language. In this article, we'll explore the difference between passing slices by value and by reference, and how it impacts the modification of slices within functions. Introduction In Go, slices are a fundamental data structure used to work with sequences of elements. They are essentiall...

   PASS BY REFERENCE,ARRAY,SLICE,PASS BY VALUE     2024-03-10 06:43:51

  var in JavaScript

Geoff published an article sometime ago--"How one missing var ruined our launch". This article described one case where MelonCard uses Node.js as their backend system, suddenly there was a small registration peak period--50-100 people registered concurrently, then the entire website stopped responding and many other strange problems showed up. When they were investigating the source of the problem, they found one missing var in the following code.app.all(‘/apps/:user_id/status’, fun...

   JavaScript,Scope,variable     2012-05-26 12:35:36

  Privacy & Security What Is the Difference?

                       When we discuss the internet today, there are two terms that we frequently here: privacy and security. While you may think that these two terms mean the same thing and are thus interchangeable, this isn’t true. As such, you’ll want to take a moment to learn the difference between these two terms. Understanding the Difference Between Privacy and Security When you open a checking account you share your p...

   SECURITY,PRIVACY,CYBERSECURITY     2018-12-27 00:29:57

  Linux Clock : CST,UTC and NTP setup

1. There is an option when you set up clock on installing Linux: system clock users UTC, so what does UTC mean? It's Universal Time Coordinated(UTC), there are two different times in GPS system: one is UTC , the other one is LT(Local Time). The difference between these two is just the timezone difference, UTC is the time in timezone 0. If the local time in Beijing is 8 o'clock in the morning, then UTC time is 0 o'clock, which is a 8 hour difference. 2. In Linux, when we use date to check the tim...

   Linux,Clock,UTC     2013-03-21 12:19:30

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