Tutorial by Examples: me

The simplest form of macro replacement is to define a manifest constant, as in #define ARRSIZE 100 int array[ARRSIZE]; This defines a function-like macro that multiplies a variable by 10 and stores the new value: #define TIMES10(A) ((A) *= 10) double b = 34; int c = 23; TIMES10(b); //...

func doSomething1(value: Double) { /* ... */ } func doSomething2(value: UInt) { /* ... */ } let x = 42 // x is an Int doSomething1(Double(x)) // convert x to a Double doSomething2(UInt(x)) // convert x to a UInt Integer initializers produce a runtime error if the value ove...

Classes can define properties that instances of the class can use. In this example, Dog has two properties: name and dogYearAge: class Dog { var name = "" var dogYearAge = 0 } You can access the properties with dot syntax: let dog = Dog() print(dog.name) print(dog.dogYear...

WScript.Echo "Hello world!" This displays a message on the console if run with cscript.exe (the console host) or in a message box if run with wscript.exe (the GUI host). If you're using VBScript as the server-side scripting language for a web page (for classic ASP, for example), Respo...

The second step to creating a subscription for a user is to create and execute a billing agreement, based on an existing activated billing plan. This example assumes that you have already gone through and activated a billing plan in the previous example, and have an ID for that billing plan to refer...

HTML comments can be used to leave notes to yourself or other developers about a specific point in code. They can be initiated with <!-- and concluded with -->, like so: <!-- I'm an HTML comment! --> They can be incorporated inline within other content: <h1>This part will be d...

Conditional comments can be used to customize code for different versions of Microsoft Internet Explorer. For example, different HTML classes, script tags, or stylesheets can be provided. Conditional comments are supported in Internet Explorer versions 5 through 9. Older and newer Internet Explorer ...

List Assignment If you are familiar with Perl, C, or Java, you might think that Bash would use commas to separate array elements, however this is not the case; instead, Bash uses spaces: # Array in Perl my @array = (1, 2, 3, 4); # Array in Bash array=(1 2 3 4) Create an array with new ...

Print element at index 0 echo "${array[0]}" 4.3 Print last element using substring expansion syntax echo "${arr[@]: -1 }" 4.3 Print last element using subscript syntax echo "${array[-1]}" Print all elements, each quoted separately echo "${array[@...

$.ajax({ url: 'https://api.dropboxapi.com/2/sharing/add_folder_member', type: 'POST', processData: false, data: JSON.stringify({"shared_folder_id": "84528192421","members": [{"member": {".tag": "email","email":...

An if statement checks whether a Bool condition is true: let num = 10 if num == 10 { // Code inside this block only executes if the condition was true. print("num is 10") } let condition = num == 10 // condition's type is Bool if condition { print("num is 10&...

Import the ElementTree object, open the relevant .xml file and get the root tag: import xml.etree.ElementTree as ET tree = ET.parse("yourXMLfile.xml") root = tree.getroot() There are a few ways to search through the tree. First is by iteration: for child in root: print(child.ta...

Java SE 7 As the try-catch-final statement example illustrates, resource cleanup using a finally clause requires a significant amount of "boiler-plate" code to implement the edge-cases correctly. Java 7 provides a much simpler way to deal with this problem in the form of the try-with-res...

Python 3.2+ has support for %z format when parsing a string into a datetime object. UTC offset in the form +HHMM or -HHMM (empty string if the object is naive). Python 3.x3.2 import datetime dt = datetime.datetime.strptime("2016-04-15T08:27:18-0500", "%Y-%m-%dT%H:%M:%S%z"...

Dates don't exist in isolation. It is common that you will need to find the amount of time between dates or determine what the date will be tomorrow. This can be accomplished using timedelta objects import datetime today = datetime.date.today() print('Today:', today) yesterday = today - date...

Parameters can be used for returning one or more values; those parameters are required to be non-const pointers or references. References: void calculate(int a, int b, int& c, int& d, int& e, int& f) { c = a + b; d = a - b; e = a * b; f = a / b; } Pointers: ...

Replace by position To replace a portion of a std::string you can use the method replace from std::string. replace has a lot of useful overloads: //Define string std::string str = "Hello foo, bar and world!"; std::string alternate = "Hello foobar"; //1) str.replace(6, 3,...

Given that the module from the Defining a Module section exists in the file test.js, you can import from that module and use its exported members: import {doSomething, MyClass, PI} from './test' doSomething() const mine = new MyClass() mine.test() console.log(PI) The somethingPrivate()...

A C++ namespace is a collection of C++ entities (functions, classes, variables), whose names are prefixed by the name of the namespace. When writing code within a namespace, named entities belonging to that namespace need not be prefixed with the namespace name, but entities outside of it must use t...

Creating a namespace is really easy: //Creates namespace foo namespace Foo { //Declares function bar in namespace foo void bar() {} } To call bar, you have to specify the namespace first, followed by the scope resolution operator ::: Foo::bar(); It is allowed to create one names...