Tutorial by Examples: le

NIO appeared in Java 1.4 and introduced the concept of "Channels", which are supposed to be faster than regular I/O. Network-wise, the SelectableChannel is the most interesting as it allows to monitor different states of the Channel. It works in a similar manner as the C select() system ca...

It is very common to get a StackOverflowError error while calling recursive function. Scala standard library offers TailCall to avoid stack overflow by using heap objects and continuations to store the local state of the recursion. Two examples from the scaladoc of TailCalls import scala.util.cont...

NSLog is good, but you can also log by appending to a file instead, using code like: NSFileHandle* fh = [NSFileHandle fileHandleForWritingAtPath:path]; if ( !fh ) { [[NSFileManager defaultManager] createFileAtPath:path contents:nil attributes:nil]; fh = [NSFileHandle fileHandleForWriting...

In C#, an array name and a pointer to a data type same as the array data, are not the same variable type. For example, int *p and int[] p, are not same type. You can increment the pointer variable p because it is not fixed in memory but an array address is fixed in memory, and you can't increment th...

Simple single port RAM with async read/write operations module ram_single_port_ar_aw #( parameter DATA_WIDTH = 8, parameter ADDR_WITDH = 3 )( input we, // write enable input oe, // output enable input [(ADDR_WITDH-1):0] waddr, // ...

The PATH environment variable is generally defined in ~/.bashrc or ~/.bash_profile or /etc/profile or ~/.profile or /etc/bash.bashrc (distro specific Bash configuration file) $ echo $PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jv...

To remove a PATH from a PATH environment variable, you need to edit ~/.bashrc or ~/.bash_profile or /etc/profile or ~/.profile or /etc/bash.bashrc (distro specific) file and remove the assignment for that particular path. Instead of finding the exact assignment, you could just do a replacement in t...

Model: public class SampleViewModel { public HttpPostedFileBase file {get;set;} } View: @model HelloWorldMvcApp.SampleViewModel @using (Html.BeginForm("Index","Home",FormMethod.Post, new { enctype = "multipart/form-data" })) { <div class="fo...

To interact with the filesystem you use the methods of the class Files. Checking existence To check the existence of the file or directory a path points to, you use the following methods: Files.exists(Path path) and Files.notExists(Path path) !Files.exists(path) does not neccesarily have t...

Files can be read byte- and line-wise using the Files class. Path p2 = Paths.get(URI.create("file:///home/testuser/File.txt")); byte[] content = Files.readAllBytes(p2); List<String> linesOfContent = Files.readAllLines(p2); Files.readAllLines() optionally takes a charset as para...

Files can be written bite- and line-wise using the Files class Path p2 = Paths.get("/home/testuser/File.txt"); List<String> lines = Arrays.asList( new String[]{"First line", "Second line", "Third line"}); Files.write(p2, lines); Files.writ...

Elm defines the following special type variables that have a particular meaning to the compiler: comparable: Comprised of Int, Float, Char, String and tuples thereof. This allows the use of the < and > operators. Example: You could define a function to find the smallest and largest eleme...

Renaming a table can be done in a single command: RENAME TABLE `<old name>` TO `<new name>`; The following syntax does exactly the same: ALTER TABLE `<old name>` RENAME TO `<new name>`; If renaming a temporary table, the ALTER TABLE version of the syntax must be used....

Renaming a column can be done in a single statement but as well as the new name, the "column definition" (i.e. its data type and other optional properties such as nullability, auto incrementing etc.) must also be specified. ALTER TABLE `<table name>` CHANGE `<old name>` `<n...

$ printf -v now '%(%T)T' $ echo "$now" 12:42:47

This example is directly derived from John Cooley’s design contest at SNUG’95 (Synopsys Users Group meeting). The contest was intended to oppose VHDL and Verilog designers on the same design problem. What John had in mind was probably to determine what language was the most efficient. The result...

A complex type allows you to map selected fields of a database table into a single type that is a child of the main type. [ComplexType] public class Address { public string Street { get; set; } public string Street_2 { get; set; } public string City { get; set; } public string...

CREATE TABLE [dbo].[MemOptimizedTemporalTable] ( [BusinessDocNo] [bigint] NOT NULL, [ProductCode] [int] NOT NULL, [UnitID] [tinyint] NOT NULL, [PriceID] [tinyint] NOT NULL, [SysStartTime] [datetime2](7) GENERATED ALWAYS AS ROW START NOT NULL, [SysEndTime] [datetime2](7...

This class enables a programmer to create an object and protect its confidentiality with a cryptographic algorithm. Given any Serializable object, one can create a SealedObject that encapsulates the original object, in serialized format (i.e., a "deep copy"), and seals (encrypts) its seri...

Canvas allows you to context.translate, context.rotate and context.scale in order to draw your shape in the position & size you require. Canvas itself uses a transformation matrix to efficiently track transformations. You can change Canvas's matrix with context.transform You can change Canv...