Tutorial by Examples: l

BFG Repo cleaner is an alternative to git filter-branch. It can be used to remove sensitive data or large files that were committed wrongly like binaries compiled from the source. It is written in Scala. Project website: BFG Repo Cleaner Requirements The Java Runtime Environment (Java 7 or above ...

When interfacing with C APIs, one might want to back off Swift reference counter. Doing so is achieved with unmanaged objects. If you need to supply a type-punned pointer to a C function, use toOpaque method of the Unmanaged structure to obtain a raw pointer, and fromOpaque to recover the original ...

; IF d0 == 10 GO TO ten, ELSE GO TO other CMP #10,d0 ; compare register contents to immediate value 10 ; instruction affects the zero flag BEQ ten ; branch if zero flag set other: ; do whatever needs to be done for d0 != 10 BRA ...

The Z80 has a specific instruction to implement loop counts: DJNZstanding for "decrement B register and jump if not zero". So, B is the register of choice to implement loops on this processor. FOR...NEXT needs to be implemented "backwards", because the register counts down to zer...

Normally the jvm's garbage collection (gc) is transparent to the user (developer/engineer). GC tuning is normally not required unless the user faces a memory leak or has an application that requires large amount of memory - both of which eventually lead to an out-of-memory exception which compels t...

SampleViewModel.vb 'Import classes related to WPF for simplicity Imports System.Collections.ObjectModel Imports System.ComponentModel Public Class SampleViewModel Inherits DependencyObject 'A class acting as a ViewModel must inherit from DependencyObject 'A simple string p...

1- Define Your own custom Block typedef void(^myCustomCompletion)(BOOL); 2- Create custom method which takes your custom completion block as a parameter. -(void) customMethodName:(myCustomCompletion) compblock{ //do stuff // check if completion block exist; if we do not check it will ...

BOOL Apple's Objective-C frameworks and most Objective-C/Cocoa code uses BOOL. Use BOOL in objective-C, when dealing with any CoreFoundation APIs Boolean Boolean is an old Carbon keyword , defined as an unsigned char

The sync() method reads and fetched the model data Backbone.sync = function(method, model) { document.write("The state of the model is:"); document.write("<br>"); //The 'method' specifies state of the model document.write(method +...

Flags gulp has very few flags to know about. All other flags are for tasks to use if needed. -v or --version will display the global and local gulp versions --require <module path> will require a module before running the gulpfile. This is useful for transpilers but also has other applica...

Resource loading in Java comprises the following steps: Finding the Class or ClassLoader that will find the resource. Finding the resource. Obtaining the byte stream for the resource. Reading and processing the byte stream. Closing the byte stream. The last three steps are typically accomp...

React components that are pure functions of their props and do not require any internal state can be written as JavaScript functions instead of using the standard class syntax, as: import React from 'react' const HelloWorld = (props) => ( <h1>Hello, {props.name}!</h1> ); ...

To use typescript with react in a node project, you must first have a project directory initialized with npm. To initialize the directory with npm init Installing via npm or yarn You can install React using npm by doing the following: npm install --save react react-dom Facebook released its ow...

The simplest react component without a state and no properties can be written as: import * as React from 'react'; const Greeter = () => <span>Hello, World!</span> That component, however, can't access this.props since typescript can't tell if it is a react component. To access ...

VueJS can be used to easily handle user input as well, and the two way binding using v-model makes it really easy to change data easily. HTML : <script src="https://unpkg.com/vue/dist/vue.js"></script> <div id="app"> {{message}} <input v-model="...

This button derives from this example by Email on Acid. It is entirely code-based, so it will display without images downloaded, and the entire button is hoverable + clickable. Additionally, this example also includes spacers to help control how much vertical space appears before and after the butt...

SELECT 1 NUM_COLUMN, 'foo' VARCHAR2_COLUMN from DUAL UNION ALL SELECT NULL, NULL from DUAL; NUM_COLUMNVARCHAR2_COLUMN1foo(null)(null)

SELECT 1 a, '' b from DUAL; AB1(null)

SELECT 3 * NULL + 5, 'Hello ' || NULL || 'world' from DUAL; 3*NULL+5'HELLO'||NULL||'WORLD'(null)Hello world

SELECT a column_with_null, NVL(a, 'N/A') column_without_null FROM (SELECT NULL a FROM DUAL); COLUMN_WITH_NULLCOLUMN_WITHOUT_NULL(null)N/A NVL is useful to compare two values which can contain NULLs : SELECT CASE WHEN a = b THEN 1 WHEN a <> b THEN 0 else -1 END comparison_without_n...