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#include <stdio.h> #define is_const_int(x) _Generic((&x), \ const int *: "a const int", \ int *: "a non-const int", \ default: "of other type") int main(void) { const int i = 1; int j = 1; double...

#include <stdio.h> void print_int(int x) { printf("int: %d\n", x); } void print_dbl(double x) { printf("double: %g\n", x); } void print_default() { puts("unknown argument"); } #define print(X) _Generic((X), \ int: print_int, \ double: pri...

A lambda expression provides a concise way to create simple function objects. A lambda expression is a prvalue whose result object is called closure object, which behaves like a function object. The name 'lambda expression' originates from lambda calculus, which is a mathematical formalism invented...

On an ext filesystem, each file has a stored Access, Modification, and (Status) Change time associated with it - to view this information you can use stat myFile.txt; using flags within find, we can search for files that were modified within a certain time range. To find files that have been modifi...

To encode a string into a byte array, you can simply use the String#getBytes() method, with one of the standard character sets available on any Java runtime: byte[] bytes = "test".getBytes(StandardCharsets.UTF_8); and to decode: String testString = new String(bytes, StandardCharsets.U...

Tuples can be decomposed into individual variables with the following syntax: let myTuple = (name: "Some Name", age: 26) let (first, second) = myTuple print(first) // "Some Name" print(second) // 26 This syntax can be used regardless of if the tuple has unnamed properti...

Functions can return tuples: func tupleReturner() -> (Int, String) { return (3, "Hello") } let myTuple = tupleReturner() print(myTuple.0) // 3 print(myTuple.1) // "Hello" If you assign parameter names, they can be used from the return value: func tupleReturner(...

If you want a function to be able to throw errors, you need to add the throws keyword after the parentheses that hold the arguments: func errorThrower()throws -> String {} When you want to throw an error, use the throw keyword: func errorThrower()throws -> String { if true { retur...

In this example we're going to look at testing webhook notifications in sandbox, using ngrok to provide a tunnel for our Node HTTP listener, running on localhost, to the internet. For this example, we're going to be using Node to set up notification webhooks for payment events (such as a payment bei...

Occasionally you will find the need to encode binary data as a base64-encoded string. For this we can use the DatatypeConverter class from the javax.xml.bind package: import javax.xml.bind.DatatypeConverter; import java.util.Arrays; // arbitrary binary data specified as a byte array byte[] bi...

Java SE 5 public enum Singleton { INSTANCE; public void execute (String arg) { // Perform operation here } } Enums have private constructors, are final and provide proper serialization machinery. They are also very concise and lazily initialized in a thread safe manne...

Writing bytes to an OutputStream one byte at a time OutputStream stream = object.getOutputStream(); byte b = 0x00; stream.write( b ); Writing a byte array byte[] bytes = new byte[] { 0x00, 0x00 }; stream.write( bytes ); Writing a section of a byte array int offset = 1; int length = ...

This sample will show you how to update an existing webhook forwarding URL (where the notifications should be POSTed to). To run this, you should have the ID provided back by PayPal when you first created your webhooks. First, add the PayPal SDK and configure the environment (sandbox below). var p...

Since the new line separator varies from platform to platform (e.g. \n on Unix-like systems or \r\n on Windows) it is often necessary to have a platform-independent way of accessing it. In Java it can be retrieved from a system property: System.getProperty("line.separator") Java SE 7 ...

To load a properties file bundled with your application: public class Defaults { public static Properties loadDefaults() { try (InputStream bundledResource = Defaults.class.getResourceAsStream("defaults.properties")) { Properties defaults = new ...

First, establish if the device is capable of accepting Touch ID input. if (context.CanEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, out AuthError)) If it does then we can display the Touch ID UI by using: context.EvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometri...

HTTPGetJSON performs an HTTP request to the specified URL and returns a jsonq.JsonQuery object for use in the alert template. Example: template example { {{ $ip := 8.8.8.8 }} {{ $whoisURL := printf "http://whois.arin.net/rest/ip/%s" $ip }} {{ $whoisJQ := $.HTTPGetJSON $who...

To begin, install Node.js on your development computer. Windows: Navigate to the download page and download/run the installer. Mac: Navigate to the download page and download/run the installer. Alternatively, you can install Node via Homebrew using brew install node. Homebrew is a command-line pac...

Java SE 7 byte[] bytes = { 0x48, 0x65, 0x6c, 0x6c, 0x6f }; try(FileOutputStream stream = new FileOutputStream("Hello world.txt")) { stream.write(bytes); } catch (IOException ioe) { // Handle I/O Exception ioe.printStackTrace(); } Java SE 7 byte[] bytes = { 0x48, ...

Browse to File > New > Solution to bring you up the new project dialog. Select Android App and press Next. Configure your app by setting your app name and organization ID. Select the Target Platform most suited for your needs, or leave it as the default. Press Next: Set your Project name ...