Tutorial by Examples: er

Floating point literals

Floating point literals are used to represent signed real numbers. The following suffixes can be used to specify type of a literal: SuffixTypeExamplesnonedouble3.1415926 -3E6f, Ffloat3.1415926f 2.1E-6Fl, Llong double3.1415926L 1E126L In order to use these suffixes, the literal must be a floating p...

C Language • Literals for numbers, characters and strings

Character literals

Character literals are a special type of integer literals that are used to represent one character. They are enclosed in single quotes, e.g. 'a' and have the type int. The value of the literal is an integer value according to the machine's character set. They do not allow suffixes. The L prefix bef...

C Language • Literals for numbers, characters and strings

Accessing Parameters

When executing a Bash script, parameters passed into the script are named in accordance to their position: $1 is the name of the first parameter, $2 is the name of the second parameter, and so on. A missing parameter simply evaluates to an empty string. Checking for the existence of a parameter can...

Bash • Scripting with Parameters

How do foldFree and iterM work?

There are some functions to help tear down Free computations by interpreting them into another monad m: iterM :: (Functor f, Monad m) => (f (m a) -> m a) -> (Free f a -> m a) and foldFree :: Monad m => (forall x. f x -> m x) -> (Free f a -> m a). What are they doing? First l...

Haskell Language • Free Monads

IComparable as an Example of Implementing an Interface

Interfaces can seem abstract until you seem them in practice. The IComparable and IComparable<T> are great examples of why interfaces can be helpful to us. Let's say that in a program for a online store, we have a variety of items you can buy. Each item has a name, an ID number, and a price. ...

C# Language • Interfaces

Parsing JavaScript Generated Page with Jsoup and HtmUnit

page.html - source code <html> <head> <script src="loadData.js"></script> </head> <body onLoad="loadData()"> <div class="container"> <table id="data" border="1"> <...

Jsoup • Parsing Javascript Generated Pages

Multiline string literals

VB now allows string literals that split over multiple lines. Old syntax: Dim text As String = "Line1" & Environment.NewLine & "Line2" New syntax: Dim text As String = "Line 1 Line 2"

Visual Basic .NET Language • Visual Basic 14.0 Features

How to compose values and functions using common operators

In Object Oriented Programming a common task is to compose objects (values). In Functional Programming it is as common task to compose values as well as functions. We are used to compose values from our experience of other programming languages using operators like +, -, *, / and so on. Value co...

F# • Operators

Latebinding in F# using ? operator

In a statically typed language like F# we work with types well-known at compile-time. We consume external data sources in a type-safe manner using type providers. However, occassionally there's need to use late binding (like dynamic in C#). For instance when working with JSON documents that have...

F# • Operators

Object Initializers

Named Types Dim someInstance As New SomeClass(argument) With { .Member1 = value1, .Member2 = value2 '... } Is equivalent to Dim someInstance As New SomeClass(argument) someInstance.Member1 = value1 someInstance.Member2 = value2 '... Anonymous Types (Option...

Visual Basic .NET Language • Introduction to Syntax

Collection Initializer

Arrays Dim names = {"Foo", "Bar"} ' Inferred as String() Dim numbers = {1, 5, 42} ' Inferred as Integer() Containers (List(Of T), Dictionary(Of TKey, TValue), etc.) Dim names As New List(Of String) From { "Foo", "Bar" '... ...

Visual Basic .NET Language • Introduction to Syntax

Dictionaries are unordered

You might expect a Python dictionary to be sorted by keys like, for example, a C++ std::map, but this is not the case: myDict = {'first': 1, 'second': 2, 'third': 3} print(myDict) # Out: {'first': 1, 'second': 2, 'third': 3} print([k for k in myDict]) # Out: ['second', 'third', 'first'] Py...

Python Language • Common Pitfalls

POSIX Timer with SIGEV_THREAD notification

This example demonstrates POSIX Timer usage with CLOCK_REALTIME clock and SIGEV_THREAD notification method. #include <stdio.h> /* for puts() */ #include <string.h> /* for memset() */ #include <unistd.h> /* for sleep() */ #include <stdlib.h> /* for EXIT_SUCCESS */ #inc...

POSIX • Timers

Multiple Routes

The main app file loads any routes files in which you would like to define routes. To do so we need the following directory structure: app.js routes/index.js routes/users.js app.js var express = require('express'); var app = express(); app.use('/', require('./routes/index')); app.use('/us...

express • Routing

SQLiteOpenHelper with fully qualified DB path name/databse in public folder

Normally Android-SQLiteOpenHelper does not allow fully qualified path names where the database should be stored. So public database files are not possible. You can use the SQLiteOpenHelper with a custom path if you provide a custom ContextClass and if you have write access in the target directory. ...

android-sqlite • SQLiteOpenHelper

Verifying Arguments with ArgumentMatcher

Mockito provides a Matcher<T> interface along with an abstract ArgumentMatcher<T> class to verify arguments. It uses a different approach to the same use-case than the ArgumentCaptor. Additionally the ArgumentMatcher can be used in mocking too. Both use-cases make use of the Mockito.argT...

mockito • Getting started with mockito

Using Pools and Workers

Pooling provides a higher level abstraction of the Worker functionality, including the management of references in the way required by pthreads. From: http://php.net/manual/en/class.pool.php Pools and workers provide an higher level of control and ease of creating multi-threaded <?php // T...

PHP • Multi Threading Extension

Universal Module Definition (UMD)

The UMD (Universal Module Definition) pattern is used when our module needs to be imported by a number of different module loaders (e.g. AMD, CommonJS). The pattern itself consists of two parts: An IIFE (Immediately-Invoked Function Expression) that checks for the module loader that is being i...

JavaScript • Modularization Techniques

Before vs. After Middleware

An example of "before" middleware would be as follows: <?php namespace App\Http\Middleware; use Closure; class BeforeMiddleware { public function handle($request, Closure $next) { // Perform action return $next($request); } } while &quot...

Laravel • Middleware

Adapters and Consumers

Iterator methods can be broken into two distinct groups: Adapters Adapters take an iterator and return another iterator // Iterator Adapter // | | let my_map = (1..6).map(|x| x * x); println!("{:?}", my_map); Output Map { iter: 1..6 } Note that the v...

Rust • Iterators