Tutorial by Examples: b

Sometimes loop condition should be checked in the middle of the loop. The former is arguably more elegant than the latter: for (;;) { // precondition code that can change the value of should_end_loop expression if (should_end_loop) break; // do something } Alternati...

CMake knows several build types, which usually influence default compiler and linker parameters (such as debugging information being created) or alternative code paths. By default, CMake is able to handle the following build types: Debug: Usually a classic debug build including debugging informa...

You can add an interpreter directive (shebang) to your script. Create a file called hello_world.rb which contains: #!/usr/bin/env ruby puts 'Hello World!' Give the script executable permissions. Here's how to do that in Unix: $ chmod u+x hello_world.rb Now you do not need to call the Ru...

This program uses the Windows API (WinAPI) to print "Hello World" into a message box. To include a dependency (like Windows in this case), add the uses block including a comma-separated list of units ending with an semicolon. program HelloWorld; uses Windows; begin MessageBox...

Prerequisite: Installing Gradle Once you have Gradle installed, you can setup a new or existing project by running cd $PROJECT_DIR gradle init --type=java-library Note that there are other project types like Scala you can get started with, but we'll use Java for this example. You will end up ...

Incorrect usage: In the following snippet, the last match will never be used: let x = 4 match x with | 1 -> printfn "x is 1" | _ -> printfn "x is anything that wasn't listed above" | 4 -> printfn "x is 4" prints x is anything that wasn't listed abov...

type Person = { Age : int PassedDriversTest : bool } let someone = { Age = 19; PassedDriversTest = true } match someone.PassedDriversTest with | true when someone.Age >= 16 -> printfn "congrats" | true -> printfn "wait until you are 16" | false -> p...

>>> variables = {'a': 6, 'b': 7} >>> eval('a * b', globals=variables) 42 As a plus, with this the code cannot accidentally refer to the names defined outside: >>> eval('variables') {'a': 6, 'b': 7} >>> eval('variables', globals=variables) Traceback (most ...

int x = 5 / 0; // Undefined behavior Division by 0 is mathematically undefined, and as such it makes sense that this is undefined behavior. However: float x = 5.0f / 0.0f; // x is +infinity Most implementation implement IEEE-754, which defines floating point division by zero to return N...

By default, Django renders ForeignKey fields as a <select> input. This can cause pages to be load really slowly if you have thousands or tens of thousand entries in the referenced table. And even if you have only hundreds of entries, it is quite uncomfortable to look for a particular entry amo...

In a non-strict-mode scope, when a variable is assigned without being initialized with the var, const or the let keyword, it is automatically declared in the global scope: a = 12; console.log(a); // 12 In strict mode however, any access to an undeclared variable will throw a reference error: &...

Differences in subsetting syntax A data.table is one of several two-dimensional data structures available in R, besides data.frame, matrix and (2D) array. All of these classes use a very similar but not identical syntax for subsetting, the A[rows, cols] schema. Consider the following data stored i...

Category theory is a modern mathematical theory and a branch of abstract algebra focused on the nature of connectedness and relation. It is useful for giving solid foundations and common language to many highly reusable programming abstractions. Haskell uses Category theory as inspiration for some o...

It is not possible to use eval or exec to execute code from untrusted user securely. Even ast.literal_eval is prone to crashes in the parser. It is sometimes possible to guard against malicious code execution, but it doesn't exclude the possibility of outright crashes in the parser or the tokenizer....

<div class="navbar navbar-inverse navbar-fixed-top"> <div class="container"> <div class="navbar-header"> <!--- vvv Hamburger icon that gets shown when window reaches a certain scale vvv ---> <button type...

<div class="navbar navbar-inverse navbar-fixed-top"> <div class="container"> <div class="navbar-header"> <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".n...

<div class="navbar navbar-inverse navbar-fixed-top"> <div class="container"> <div class="navbar-header"> <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".n...

using System; using System.Web; using System.Web.Mvc; namespace Example.SDK.Filters { [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)] public sealed class CustomErrorHandlerFilter : HandleErrorAttribute { public override void OnExceptio...

With ASP.NET Core 1.0, the MVC and Web API framework have been merged into one framework called ASP.NET Core MVC. This is a good thing, since MVC and Web API share a lot of functionality, yet there always were subtle differences and code duplication. However, merging these two into framework one ...

LOOP AT itab INTO wa. ENDLOOP. FIELD-SYMBOLS <fs> LIKE LINE OF itab. LOOP AT itab ASSIGNING <fs>. ENDLOOP. LOOP AT itab ASSIGNING FIELD-SYMBOL(<fs>). ENDLOOP. LOOP AT itab REFERENCE INTO dref. ENDLOOP. LOOP AT itab TRANSPORTING NO FIELDS. ENDLOOP. Conditional L...