Tutorial by Examples: le

When reading from a file, we want to be able to know when we've reached the end of that file. Knowing that fgets() returns false at the end of the file, we might use this as the condition for a loop. However, if the data returned from the last read happens to be something that evaluates as boolean f...

Using the Story Board: Select the tab bar item from the corresponding view controller and go to the attributes inspector If you want a built-in icon and title, set the 'System Item' to the corresponding value. For a custom icon, add the required images to the assets folder and set the 'System It...

If you need to delete a lot of records quickly, ActiveRecord gives .delete_all method. to be called directly on a model, to delete all records in that table, or a collection. Beware though, as .delete_all does not instantiate any object hence does not provide any callback (before_* and after_destroy...

It is very rare that you'll ever want to use Select or Activate in your code, but some Excel methods do require a worksheet or workbook to be activated before they'll work as expected. If you're just starting to learn VBA, you'll often be suggested to record your actions using the macro recorder, t...

// You need a writable database to update a row final SQLiteDatabase database = openHelper.getWritableDatabase(); // Create a ContentValues instance which contains the up to date data for each column // Unlike when inserting data you need to specify the value for the PRIMARY KEY column as well ...

Orders Table CustomerIdProductIdQuantityPrice12510013220014150021450356700 To check for customers who have ordered both - ProductID 2 and 3, HAVING can be used select customerId from orders where productID in (2,3) group by customerId having count(distinct productID) = 2 Return value:...

This simple CUDA program demonstrates how to write a function that will execute on the GPU (aka "device"). The CPU, or "host", creates CUDA threads by calling special functions called "kernels". CUDA programs are C++ programs with additional syntax. To see how it works...

Some basic types and classes in Java are fundamentally mutable. For example, all array types are mutable, and so are classes like java.util.Data. This can be awkward in situations where an immutable type is mandated. One way to deal with this is to create an immutable wrapper for the mutable type...

static int Sum(int a, int b) { return a + b; } static int Multiplication(int a, int b) { return a * b; } static void Main(string[] args) { Func<int, int, int> method = Sum; // method points to the Sum method // that retuns 1 int variable and takes 2 int vari...

An immutable object is an object whose state cannot be changed. An immutable class is a class whose instances are immutable by design, and implementation. The Java class which is most commonly presented as an example of immutability is java.lang.String. The following is a stereotypical example: ...

In most cases, you may want to set I18n locale. One might want to set the locale for the current session, the current user, or based on a URL parameter This is easily achievable by implementing a before_action in one of your controllers, or in ApplicationController to have it in all of your controll...

A boolean represents the most basic datatype in TypeScript, with the purpose of assigning true/false values. // set with initial value (either true or false) let isTrue: boolean = true; // defaults to 'undefined', when not explicitely set let unsetBool: boolean; // can ...

Array type with known and possibly different types: let day: [number, string]; day = [0, 'Monday']; // valid day = ['zero', 'Monday']; // invalid: 'zero' is not numeric console.log(day[0]); // 0 console.log(day[1]); // Monday day[2] = 'Saturday'; // valid: [0, 'Saturday'] day[3] = fals...

Specially useful for has_and_belongs_to_many relation, you can manually create a join table using the create_table method. Suppose you have two models Tags and Proyects, and you'd like to associate them using a has_and_belongs_to_many relation. You need a join table to associate instances of both c...

CSS styles for the credits label. Defaults to: credits: { style: { cursor: 'pointer', color: '#909090', fontSize: '10px' } },

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), ...

In most examples, the class naming convention is used to define an Aurelia Custom Element. However, Aurelia also provides a decorator that can be used to decorate a class. The class is again treated as a custom element by Aurelia then. The value supplied to the decorator becomes the name of the cus...

You can declare multiple constants within the same const block: const ( Alpha = "alpha" Beta = "beta" Gamma = "gamma" ) And automatically increment constants with the iota keyword: const ( Zero = iota // Zero == 0 One // One == 1...

let sel = document.getSelection(); sel.removeAllRanges();

let sel = document.getSelection(); let myNode = document.getElementById('element-to-select'); let range = document.createRange(); range.selectNodeContents(myNode); sel.addRange(range); It may be necessary to first remove all the ranges of the previous selection, as most browsers don't s...