Tutorial by Examples: am

Let's have a basic failing program: #include <iostream> void fail() { int *p1; int *p2(NULL); int *p3 = p1; if (p3) { std::cout << *p3 << std::endl; } } int main() { fail(); } Build it (add -g to include debug info): g++ -g -o m...
Let's say we need to add a button for each piece of loadedData array (for instance, each button should be a slider showing the data; for the sake of simplicity, we'll just alert a message). One may try something like this: for(var i = 0; i < loadedData.length; i++) jQuery("#container&q...
The __info__/1 function takes one of the following atoms: :functions - Returns a keyword list of public functions along with their arities :macros - Returns a keyword list of public macros along with their arities To list the Kernel module’s functions: iex> Kernel.__info__ :functions [...
Use keyword lists for 'options'-style parameters that contains multiple key-value pairs: def myfunc(arg1, opts \\ []) do # Function body end We can call the function above like so: iex> myfunc "hello", pizza: true, soda: false which is equivalent to: iex> myfunc("he...
assert ['cat', 'dog', 'fish']*.length() == [3, 3, 4] Note that when mixing types in the collection if the method not exists on some of the elements, a groovy.lang.MissingMethodException could be thrown: ['cat', 'dog', 'fish',3]*.length() // it throws groovy.lang.MissingMethodException: No sign...
The following example is an introduction to: Template compilation using underscore Accessing variables in a template Creating a view Rendering a view Showing a view <html> <head> <script src="https://code.jquery.com/jquery-3.1.0.min.js"></script> ...
Query to create table on db CREATE TABLE `user` ( `id` smallint(5) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(30) NOT NULL, `course` smallint(5) unsigned DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB; CREATE TABLE `course` ( `id` smallint(5) unsigned NOT NULL AUTO_INCREMENT, `nam...
Unlike other middleware functions error-handling middleware functions have four arguments instead of three: (err, req, res, next). Sample: app.use(function(err, req, res, next) { console.error(err.stack); res.status(500).send('Error found!'); });
A module is an importable file containing definitions and statements. A module can be created by creating a .py file. # hello.py def say_hello(): print("Hello!") Functions in a module can be used by importing the module. For modules that you have made, they will need to be in t...
Directives, as the name suggests, are direction or instructions for the container to follow when translating a JSP to a servlet. There are 3 directives namely page, include and taglib which you can use in your JSP. Below is a simple example of using page directive: <%@ page isErrorPage="tr...
Leaflet is an open-source JavaScript library for making dynamic maps for the web. RStudio wrote R bindings for Leaflet, available through its leaflet package, built with htmlwidgets. Leaflet maps integrate well with the RMarkdown and Shiny ecosystems. The interface is piped, using a leaflet() funct...
This example shows how to create a delegate that encapsulates the method that returns the current time static DateTime UTCNow() { return DateTime.UtcNow; } static DateTime LocalNow() { return DateTime.Now; } static void Main(string[] args) { Func<DateTime> method = U...
An anonymous method can be assigned wherever a delegate is expected: Func<int, int> square = delegate (int x) { return x * x; } Lambda expressions can be used to express the same thing: Func<int, int> square = x => x * x; In either case, we can now invoke the method stored ins...
Func also supports Covariant & Contravariant // Simple hierarchy of classes. public class Person { } public class Employee : Person { } class Program { static Employee FindByTitle(String title) { // This is a stub for a method that returns // an employee that h...
The double-colon syntax of names in the use statement looks similar to names used elsewhere in the code, but meaning of these paths is different. Names in the use statement by default are interpreted as absolute, starting at the crate root. Names elsewhere in the code are relative to the current mo...
GetLastError returns a numerical error code. To obtain a descriptive error message (e.g., to display to a user), you can call FormatMessage: // This functions fills a caller-defined character buffer (pBuffer) // of max length (cchBufferLength) with the human-readable error message // for a Win32 ...
Occasionally you may want to use the same tuple type in multiple places throughout your code. This can quickly get messy, especially if your tuple is complex: // Define a circle tuple by its center point and radius let unitCircle: (center: (x: CGFloat, y: CGFloat), radius: CGFloat) = ((0.0, 0.0), ...
package { import flash.events.TimerEvent; import flash.utils.Timer; public class CountdownTimer extends Timer { public var time:Number = 0; public function CountdownTimer(time:Number = Number.NEGATIVE_INFINITY, delay:Number = 1000) { super(delay, repeatCount); ...
ga('create', 'UA-XXXX-Y', {'sampleRate': 5}); Optional. This may only be set in the create method. Specifies what percentage of users should be tracked. This defaults to 100 (no users are sampled out) but large sites may need to use a lower sample rate to stay within Google Analytics processing ...
Before ECMAScript 2015 (ES6), a parameter's default value could be assigned in the following way: function printMsg(msg) { msg = typeof msg !== 'undefined' ? // if a value was provided msg : // then, use that value in the reassignemnt 'Default value for ...

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