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  How to check whether a struct implements an interface in GoLang

Unlike other programming languages like Java, when implementing an interface in GoLang, there is no syntax like below to explicit tell the relationship: type I interface { } type A struct implements I { } When looking at the code or running the code in GoLang, it might lead to a case one doesn't know whether a struct implements interface before trying to use it as some interface. According to GoLang spec, as long as a struct implements all functions of an interface, it is considered as having i...

   GOLANG,INTERFACE,IMPLEMENTATION,CHECK     2020-05-03 00:05:54

  Introduction to GoLang generics and advanced usage

Generics in Go allow you to write code that can work with multiple types of data, without having to write separate versions of the code for each type. This can make your code more flexible and easier to maintain, as you only need to write and test the code once, rather than maintaining multiple versions. To use generics in Go, you first need to define a type parameter, which is a placeholder for the type that the code will work with. For example, you might define a type parameter called "T" like...

   GOLANG,GENERICS     2022-12-17 05:12:21

  Be careful about nil check on interface in GoLang

nil check is frequently seen in GoLang code especially for error check since GoLang's special error handling convention. In most cases, nil check is straight forward, but in interface case, it's a bit different and special care needs to be taken. Take a look at below code snippet and guess what the output will be. package main import ( "bytes" "fmt" "io" ) func check(w io.Writer) { if w != nil { fmt.Println("w is not nil") } fmt.Printf("w is %+v\n", w) } func main() { var b *bytes.B...

   INTERFACE,GOLANG,NIL CHECK,NIL TYPE,NIL VALUE     2019-04-06 07:47:07

  The Strange Behavior of the void Type in TypeScript

Preface In TypeScript (TS), there is a type called void. It represents "nothing" but it's important to note that it's not the same as "nothing" in JavaScript(JS). Typically, void is used to declare the return type of functions. Although you can declare a variable as void, we generally don't do this because it serves no meaningful purpose. Let's explore why in the examples below. The void Type Declaring a Variable as void let name: void; // Declare a variable `name` with type `void`. name = 'nan...

   TYPESCRIPT,JAVASCRIPT,VOID,TYPE     2024-09-13 23:44:26

  template function in class in C++

We can define template function in a class, but one thing we should pay attention to is that the member function template definition (in addition to the declaration) should be in the header file, not the cpp, though it does not have to be in the body of the class declaration itself.Example //Sorter.h#pragma onceclass Sorter{public:    Sorter(void);    ~Sorter(void);    template <class type> static void qsort(type arr[],int start,int end);};templ...

   C++,template function,class,definition,d     2011-08-07 09:39:56

  Data type in MySQL

For both small free database space and large e-commerce websites, reasonable database table structure design is essential. To achieve this, it requires us to have a full understanding of commonly used data types in database system. Below we share some knowledge about data types in MySQL.1. Numeric typesThe numeric types can be classified as : integer, float and decimal type.The so-called "decimal" refers DECIMAL and NUMERIC, they are of the same type. Strictly speaking it is not a numeric type, ...

   MySQL, Data type,VARCHAR     2013-01-01 10:56:06

  Steps to connect to MySQL on Windows Command Line

To connect to MySQL database on Windows through Command line, there are some steps to be followed.1. You need to start the MySQL service, you can go to Start->Control Panel->System and Securities->Administrative Tools->Component Service->Services(local), then on the right panel, you can find one service name called MySQL and you should start this service2. Go the the MySQL installation folder, which is something like this : C:\Program Files\MySQL\MySQL Server 5.1. In this folder, ...

   MySQL,Window,Command line,Connection,mysqld     2011-11-05 08:22:39

  Ensuring Go Interface Implementation: A Quick Guide

Introduction Go's simplicity and power shine in its interface system, offering a clean way to define contracts between types. However, when it comes to checking whether a struct satisfies an interface, Go's static typing philosophy means there isn't a direct runtime check. In this concise guide, we'll explore practical methods, including some lesser-known tricks, to verify whether a struct implements an interface. Method 1: Type Assertion and a Dummy Method package main import "fmt" type MyInt...

   INTERFACE,GOLANG,IMPLEMENTS     2023-11-25 21:36:01

  Let browser prompt for storing password when doing AJAX login

In Web 2.0 era, more and more web applications are using AJAX to replace the traditional HTML form element to perform user login. This usually provides a better user experience than form submission. But it also brings a side effect to the end users. That is the browser will not prompt the user whether s/he wants to save the password so that s/he no needs to enter the username/password again when visiting the same site next time. Below is the code snippet which does the AJAX login.  <scri...

   AJAX,Browser,Login,Password     2015-06-04 10:02:46

  Time to think about supporting max/min functions for integers in GoLang

Sometime back we wrote a post explaining why there is no max/min function support for integers in GoLang, one of the reasons is that no overloading is supported and the function name has been used for other numeric types float64. To solve this problem and make max/min function support integer as well, either GoLang should support overloading like in Java or the same set of functions need to be created in a different package other than standard math. These don't look like good options as overload...

   MIN,MAX,GENERICS,GOLANG     2021-07-24 03:14:42