Tutorial by Examples: re

A stream is an object that provides a low-level means to transfer data. They themselves do not act as data containers. The data that we deal with is in form of byte array(byte []). The functions for reading and writing are all byte orientated, e.g. WriteByte(). There are no functions for dealing w...

Java and most other languages store negative integral numbers in a representation called 2's complement notation. For a unique binary representation of a data type using n bits, values are encoded like this: The least significant n-1 bits store a positive integral number x in integral representati...

Casting an instance of a base class to a subclass as in : b = (B) a; is called narrowing (as you are trying to narrow the base class object to a more specific class object) and needs an explicit type-cast. Casting an instance of a subclass to a base class as in: A a = b; is called widening and does...

If we try to change an object on the UI thread from a different thread we will get a cross-thread operation exception: Private Sub Button_Click(sender As Object, e As EventArgs) Handles MyButton.Click ' Cross thread-operation exception as the assignment is executed on a different thread '...

Random and ThreadLocalRandom are good enough for everyday use, but they have a big problem: They are based on a linear congruential generator, an algorithm whose output can be predicted rather easily. Thus, these two classes are not suitable for cryptographic uses (such as key generation). One can ...

Using sw As New System.IO.StreamWriter("path\to\file.txt") sw.WriteLine("Hello world") End Using The use of a Using block is recommended good practice when using an object that Implements IDisposable

std::ifstream f("file.txt"); if (f) { std::stringstream buffer; buffer << f.rdbuf(); f.close(); // The content of "file.txt" is available in the string `buffer.str()` } The rdbuf() method returns a pointer to a streambuf that can be pushed into buffer...

Most times when people have to reverse a string, they do it more or less like this: char[] a = s.ToCharArray(); System.Array.Reverse(a); string r = new string(a); However, what these people don't realize is that this is actually wrong. And I don't mean because of the missing NULL check. It ...

Creating backpressured data sources is the relatively easier task when dealing with backpressure in general because the library already offers static methods on Observable that handle backpressure for the developer. We can distinguish two kinds of factory methods: cold "generators" that ei...

Basic HTTP calls don't provide code-reusability, however. And they can get confused with all the other features you're trying to implement. For those reasons, it's common to implement an API wrapper. Foo = { identify: function(input){ return Http.get('http://foo.net/api/identify/' + input...

After creating an API wrapper, it's likely that you may want to create an Atmosphere package to redistribute it and share it between applications. The files of your package will probably look something like this. packages/foo-api-wrapper/package.js packages/foo-api-wrapper/readme.md packages/foo-...

We can also use macros for making code easier to read and write. For example we can implement macros for implementing the foreach construct in C for some data structures like singly- and doubly-linked lists, queues, etc. Here is a small example. #include <stdio.h> #include <stdlib.h>...

def arg = [phrase: 'interpolated'] assert "This is $arg.phrase" == 'This is interpolated'

def str = 'old' def interpolated = "I am the ${str} value" assert interpolated == 'I am the old value' str = 'new' assert interpolated == 'I am the old value'

We can have lazy interpolation in Strings. This is different than normal interpolation as the GString can potentially have different values, depending on the closure, whenever it is converted into a String. def str = 'old' def interpolated = "I am the ${ -> str} value" assert interpo...

def str = 'dsl' def interpolated = "Groovy ${str.length() + 1} easy ${str.toUpperCase()}" assert interpolated == 'Groovy 4 easy DSL' str = 'Domain specific language' assert interpolated == 'Groovy 4 easy DSL'

Given two types T and U, &T will coerce (implicitly convert) to &U if and only if T implements Deref<Target=U> This allows us to do things like this: fn foo(a: &[i32]) { // code } fn bar(s: &str) { // code } let v = vec![1, 2, 3]; foo(&v); // &Vec&l...

As well as being able to create an array by filtering out nil from the transformed elements of a sequence, there is also a version of flatMap(_:) that expects the transformation closure to return a sequence S. extension SequenceType { public func flatMap<S : SequenceType>(transform: (Sel...

4.0 Instead of the ForEach-Object cmdlet, the here is also the possibility to use a ForEach method directly on object arrays like so (1..10).ForEach({$_ * $_}) or - if desired - the parentheses around the script block can be omitted (1..10).ForEach{$_ * $_} Both will result in the output ...

A branch is just a pointer to a commit, so you can freely move it around. To make it so that the branch is referring to the commit aabbcc, issue the command git reset --hard aabbcc Please note that this will overwrite your branch's current commit, and as so, its entire history. You might loose s...