Tutorial by Examples: ha

C11 Reading an object will cause undefined behavior, if the object is1: uninitialized defined with automatic storage duration it's address is never taken The variable a in the below example satisfies all those conditions: void Function( void ) { int a; int b = a; } 1 (Quo...

// Convert string to ArrayBuffer. This step is only necessary if you wish to hash a string, not if you aready got an ArrayBuffer such as an Uint8Array. var input = new TextEncoder('utf-8').encode('Hello world!'); // Calculate the SHA-256 digest crypto.subtle.digest('SHA-256', input) // Wait fo...

You can see what "hunks" of work would be staged for commit using the patch flag: git add -p or git add --patch This opens an interactive prompt that allows you to look at the diffs and let you decide whether you want to include them or not. Stage this hunk [y,n,q,a,d,/,s,e,?]? ...

Generic methods allow the use of anonymous types through type inference. void Log<T>(T obj) { // ... } Log(new { Value = 10 }); This means LINQ expressions can be used with anonymous types: var products = new[] { new { Amount = 10, Id = 0 }, new { Amount = 20, Id = 1 }, ...

Using generic constructors would require the anonymous types to be named, which is not possible. Alternatively, generic methods may be used to allow type inference to occur. var anon = new { Foo = 1, Bar = 2 }; var anon2 = new { Foo = 5, Bar = 10 }; List<T> CreateList<T>(params T[] it...

VoiceOver works great most of the time, breezily reading aloud screens full of content and intuitively following the user. Alas, no general solution is perfect. Sometimes only you, the app developer, know where VoiceOver should be focused for an optimal user experience. Fortunately, VoiceOver listen...

In many cases, content within a single screen will update with new or different content. For example, imagine a form that reveals additional options based on the user’s answer to a previous question. In this case, a “layout change” notification lets you either announce the change or focus on a new e...

HandleFunc registers the handler function for the given pattern in the server mux (router). You can pass define an anonymous function, as we have seen in the basic Hello World example: http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintln(w, "Hello, w...

In Go errors can be returned from a function call. The convention is that if a method can fail, the last returned argument is an error. func DoAndReturnSomething() (string, error) { if os.Getenv("ERROR") == "1" { return "", errors.New("The method fai...

The getAll() method retrieves all values from the preferences. We can use it, for instance, to log the current content of the SharedPreferences: private static final String PREFS_FILE = "MyPrefs"; public static void logSharedPreferences(final Context context) { SharedPreferences s...

To show all staged and unstaged changes, use: git diff HEAD NOTE: You can also use the following command: git status -vv The difference being that the output of the latter will actually tell you which changes are staged for commit and which are not.

apply is used to evaluate a function (maybe an anonymous one) over the margins of an array or matrix. Let's use the iris dataset to illustrate this idea. The iris dataset has measurements of 150 flowers from 3 species. Let's see how this dataset is structured: > head(iris) Sepal.Length Sep...

Default behaviour is when the merge resolves as a fast-forward, only update the branch pointer, without creating a merge commit. Use --no-ff to resolve. git merge <branch_name> --no-ff -m "<commit message>"

Even just reading the value of a pointer that was freed (i.e. without trying to dereference the pointer) is undefined behavior(UB), e.g. char *p = malloc(5); free(p); if (p == NULL) /* NOTE: even without dereferencing, this may have UB */ { } Quoting ISO/IEC 9899:2011, section 6.2.4 §2: ...

This example requires the headers <algorithm>, <locale>, and <utility>. C++11 To trim a sequence or string means to remove all leading and trailing elements (or characters) matching a certain predicate. We first trim the trailing elements, because it doesn't involve moving any el...

Errors thrown from promises are handled by the second parameter (reject) passed to then or by the handler passed to catch: throwErrorAsync() .then(null, error => { /* handle error here */ }); // or throwErrorAsync() .catch(error => { /* handle error here */ }); Chaining If you hav...

A custom component that takes the type of a component as input and creates an instance of that component type inside itself. When the input is updated, the previously added dynamic component is removed and the new one added instead. @Component({ selector: 'dcl-wrapper', template: `<div #...

This example is a quick setup of Angular 2 and how to generate a quick example project. Prerequisites: Node.js v4 or greater. npm v3 or greater or yarn. Open a terminal and run the commands one by one: npm install -g @angular/cli or yarn global add @angular/cli depending on your choi...

This is the Python 2 syntax, note the commas , on the raise and except lines: Python 2.x2.3 try: raise IOError, "input/output error" except IOError, exc: print exc In Python 3, the , syntax is dropped and replaced by parenthesis and the as keyword: try: raise IOErro...

To convert a String to uppercase, use uppercaseString: NSString *myString = @"Emphasize this"; NSLog(@"%@", [myString uppercaseString]; // @"EMPHASIZE THIS" To convert a String to lowercase, use lowercaseString: NSString *myString = @"NORMALIZE this"; N...