Tutorial by Examples: v

Govendor is a tool that is used to import 3rd party packages into your code repository in a way that is compatible with golang's vendoring. Say for example that you are using a 3rd party package bosun.org/slog: package main import "bosun.org/slog" func main() { slog.Infof(&quo...

A flags-style enum value needs to be tested with bitwise logic because it may not match any single value. [Flags] enum FlagsEnum { Option1 = 1, Option2 = 2, Option3 = 4, Option2And3 = Option2 | Option3; Default = Option1 | Option3, } The Default value is actually a ...

Method overloading, also known as function overloading, is the ability of a class to have multiple methods with the same name, granted that they differ in either number or type of arguments. Compiler checks method signature for method overloading. Method signature consists of three things - Met...

Method overriding is the ability of subtypes to redefine (override) the behavior of their supertypes. In Java, this translates to subclasses overriding the methods defined in the super class. In Java, all non-primitive variables are actually references, which are akin to pointers to the location of...

Objective-C CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position.x"]; animation.fromValue = @0; animation.toValue = @320; animation.duration = 1; [_label.layer addAnimation:animation forKey:@"basic"]; Swift let animation = CAB...

OBJECTIVE-C CATransition* transition = [CATransition animation]; transition.startProgress = 0; transition.endProgress = 1.0; transition.type = @"flip"; transition.subtype = @"fromLeft"; transition.duration = 0.8; transition.repeatCount = 5; [_label.layer addAnimation:tran...

CGRect boundingRect = CGRectMake(-150, -150, 300, 300); CAKeyframeAnimation *orbit = [CAKeyframeAnimation animation]; orbit.keyPath = @"position"; orbit.path = CFAutorelease(CGPathCreateWithEllipseInRect(boundingRect, NULL)); orbit.duration = 4; orbit.additive = YES; orbit.repeatC...

Objective-C CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"position.x"]; animation.values = @[ @0, @10, @-10, @10, @0 ]; animation.keyTimes = @[ @0, @(1 / 6.0), @(3 / 6.0), @(5 / 6.0), @1 ]; animation.duration = 0.4; animation.additive = YES; [_label.lay...

Using reflection, a method of an object can be invoked during runtime. The example shows how to invoke the methods of a String object. import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; String s = "Hello World!"; // method without parameters // i...

The docker rmi command is used to remove images: docker rmi <image name> The full image name must be used to remove an image. Unless the image has been tagged to remove the registry name, it needs to be specified. For example: docker rmi registry.example.com/username/myAppImage:1.3.5 I...

Although not strictly required, it is highly recommended to start your project in a "virtual environment." A virtual environment is a container (a directory) that holds a specific version of Python and a set of modules (dependencies), and which does not interfere with the operating system'...

Often, we need to perform an operation over every element in a variadic template parameter pack. There are many ways to do this, and the solutions get easier to read and write with C++17. Suppose we simply want to print every element in a pack. The simplest solution is to recurse: C++11 void print...

JavaScript will try to automatically convert variables to more appropriate types upon use. It's usually advised to do conversions explicitly (see other examples), but it's still worth knowing what conversions take place implicitly. "1" + 5 === "15" // 5 got converted to string. ...

Generate a certificate In order to run a HTTPS server, a certificate is necessary. Generating a self-signed certificate with openssl is done by executing this command: openssl req -x509 -newkey rsa:4096 -sha256 -nodes -keyout key.pem -out cert.pem -subj "/CN=example.com" -days 3650` T...

Arrays are available in most programming languages, often using square [] or round () brackets to access the elements, e.g. Carray[6] or VBarray(6).

Use of global variables is generally discouraged. It makes your program more difficult to understand, and harder to debug. But sometimes using a global variable is acceptable. global.h #ifndef GLOBAL_DOT_H /* This is an "include guard" */ #define GLOBAL_DOT_H /** * This tells ...

A common pattern in C, to easily imitate returning multiple values from a function, is to use pointers. #include <stdio.h> void Get( int* c , double* d ) { *c = 72; *d = 175.0; } int main(void) { int a = 0; double b = 0.0; Get( &a , &b ); pr...

Setting a default value can be done by using Initializers (C#6) public class Name { public string First { get; set; } = "James"; public string Last { get; set; } = "Smith"; } If it is read only you can return values like this: public class Name { pu...

Invoking methods or actions in parallel (Parallel region) static void Main() { string [] urls = { "www.stackoverflow.com", "www.google.net", "www.facebook.com", "www.twitter.com" }; System.Thr...

This example aims to describe how one can utilize git rebase in interactive mode. It is expected that one has a basic understanding of what git rebase is and what it does. Interactive rebase is initiated using following command: git rebase -i The -i option refers to interactive mode. Using inte...