Tutorial by Examples: c

In C++, threads are created using the std::thread class. A thread is a separate flow of execution; it is analogous to having a helper perform one task while you simultaneously perform another. When all the code in the thread is executed, it terminates. When creating a thread, you need to pass somet...

std::this_thread is a namespace which has functions to do interesting things on the current thread from function it is called from. FunctionDescriptionget_idReturns the id of the threadsleep_forSleeps for a specified amount of timesleep_untilSleeps until a specific timeyieldReschedule running threa...

What are Array-like Objects? JavaScript has "Array-like Objects", which are Object representations of Arrays with a length property. For example: var realArray = ['a', 'b', 'c']; var arrayLike = { 0: 'a', 1: 'b', 2: 'c', length: 3 }; Common examples of Array-like Objects...

When local changes are present, the git pull command aborts reporting : error: Your local changes to the following files would be overwritten by merge In order to update (like svn update did with subversion), you can run : git stash git pull --rebase git stash pop A convenient way coul...

Unlike the WHERE clause, HAVING can be used with aggregate functions. An aggregate function is a function where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning or measurement (Wikipedia). Common aggregate function...

The STUFF() function inserts a string into another string by first deleting a specified number of characters. The following example, deletes "Svr" and replaces it with "Server". This happens by specifying the start_position and length of the replacement. SELECT STUFF('SQL Svr D...

Apple's Reachability class periodically checks the network status and alerts observers to changes. Reachability *internetReachability = [Reachability reachabilityForInternetConnection]; [internetReachability startNotifier];

Reachability uses NSNotification messages to alert observers when the network state has changed. Your class will need to become an observer. [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:) name:kReachabilityChangedNotification object:nil]; Elsewher...

- (void)reachabilityChanged:(NSNotification *)note { Reachability* reachability = [note object]; NetworkStatus netStatus = [reachability currentReachabilityStatus]; if (netStatus == NotReachable) { NSLog(@"Network unavailable"); } }

- (void)reachabilityChanged:(NSNotification *)note { Reachability* reachability = [note object]; NetworkStatus netStatus = [reachability currentReachabilityStatus]; switch (netStatus) { case NotReachable: NSLog(@"Network unavailable"); br...

Many IDEs provide support for generating HTML from Javadocs automatically; some build tools (Maven and Gradle, for example) also have plugins that can handle the HTML creation. However, these tools are not required to generate the Javadoc HTML; this can be done using the command line javadoc tool. ...

Functional Interfaces Lambdas can only operate on a functional interface, which is an interface with just one abstract method. Functional interfaces can have any number of default or static methods. (For this reason, they are sometimes referred to as Single Abstract Method Interfaces, or SAM Interf...

django-admin is a command line tool that ships with Django. It comes with several useful commands for getting started with and managing a Django project. The command is the same as ./manage.py , with the difference that you don't need to be in the project directory. The DJANGO_SETTINGS_MODULE envir...

5 Object.freeze makes an object immutable by preventing the addition of new properties, the removal of existing properties, and the modification of the enumerability, configurability, and writability of existing properties. It also prevents the value of existing properties from being changed. Howev...

5 Object.seal prevents the addition or removal of properties from an object. Once an object has been sealed its property descriptors can't be converted to another type. Unlike Object.freeze it does allow properties to be edited. Attempts to do this operations on a sealed object will fail silently ...

// Java: List<String> list = people.stream().map(Person::getName).collect(Collectors.toList()); // Kotlin: val list = people.map { it.name } // toList() not needed

// Java: String joined = things.stream() .map(Object::toString) .collect(Collectors.joining(", ")); // Kotlin: val joined = things.joinToString() // ", " is used as separator, by default

// Java: int total = employees.stream() .collect(Collectors.summingInt(Employee::getSalary))); // Kotlin: val total = employees.sumBy { it.salary }

// Java: Map<Department, Integer> totalByDept = employees.stream() .collect(Collectors.groupingBy(Employee::getDepartment, Collectors.summingInt(Employee::getSalary))); // Kotlin: val totalByDept = employees.groupBy { it.dept }.mapValues { it.v...

// Java: Arrays.stream(new int[] {1, 2, 3}) .map(n -> 2 * n + 1) .average() .ifPresent(System.out::println); // 5.0 // Kotlin: arrayOf(1,2,3).map { 2 * it + 1}.average().apply(::println)