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5 A property's descriptor can be locked so no changes can be made to it. It will still be possible to use the property normally, assigning and retrieving the value from it, but any attempt to redefine it will throw an exception. The configurable property of the property descriptor is used to dis...

5 Treat a property as a combination of two functions, one to get the value from it, and another one to set the value in it. The get property of the property descriptor is a function that will be called to retrieve the value from the property. The set property is also a function, it will be call...

Syntax: SELECT * FROM table_name Using the asterisk operator * serves as a shortcut for selecting all the columns in the table. All rows will also be selected because this SELECT statement does not have a WHERE clause, to specify any filtering criteria. This would also work the same way if you...

This query will return the number of tables in the specified database. USE YourDatabaseName SELECT COUNT(*) from INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = 'BASE TABLE' Following is another way this can be done for all user tables with SQL Server 2008+. The reference is here. SELECT COUNT(...

In this type of image addition, the image URL is included at the location where the image will be displayed. If you need to add the same image several times, you must include its URL every time. Markdown Source Picture of Duck:  HTML Output Pictu...

Note that these only work in the developer tools of certain browsers. $_ gives you the value of whatever expression was evaluated last. "foo" // "foo" $_ // "foo" $0 refers to the DOM element currently selected in the Inspector. So if &l...

In this type of image addition, one image can be used several times without duplicating its URL, making it a good choice when using one image multiple times in a document. Markdown Source Picture of Duck: ![Duck][1] Same picture of Duck: ![Same Duck][1] [1]: http://i.stack.imgur.com/uk...

Sometimes the property name needs to be stored into a variable. In this example, we ask the user what word needs to be looked up, and then provide the result from an object I've named dictionary. var dictionary = { lettuce: 'a veggie', banana: 'a fruit', tomato: 'it depends on who yo...

To find a character or another string, you can use std::string::find. It returns the position of the first character of the first match. If no matches were found, the function returns std::string::npos std::string str = "Curiosity killed the cat"; auto it = str.find("cat"); ...

The function std::find, defined in the <algorithm> header, can be used to find an element in a std::vector. std::find uses the operator== to compare elements for equality. It returns an iterator to the first element in the range that compares equal to the value. If the element in question is...

An array can easily be converted into a std::vector by using std::begin and std::end: C++11 int values[5] = { 1, 2, 3, 4, 5 }; // source array std::vector<int> v(std::begin(values), std::end(values)); // copy array to new vector for(auto &x: v) std::cout << x << &q...

When you start a thread, it will execute until it is finished. Often, at some point, you need to (possibly - the thread may already be done) wait for the thread to finish, because you want to use the result for example. int n; std::thread thread{ calculateSomething, std::ref(n) }; //Doing some...

You cannot pass a reference (or const reference) directly to a thread because std::thread will copy/move them. Instead, use std::reference_wrapper: void foo(int& b) { b = 10; } int a = 1; std::thread thread{ foo, std::ref(a) }; //'a' is now really passed as reference thread.join()...

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...

null is used for representing the intentional absence of an object value and is a primitive value. Unlike undefined, it is not a property of the global object. It is equal to undefined but not identical to it. null == undefined; // true null === undefined; // false CAREFUL: The typeof null i...

At first glance it may appear that null and undefined are basically the same, however there are subtle but important differences. undefined is the absence of a value in the compiler, because where it should be a value, there hasn't been put one, like the case of an unassigned variable. undefined...

1 / 0; // Infinity // Wait! WHAAAT? Infinity is a property of the global object (therefore a global variable) that represents mathematical infinity. It is a reference to Number.POSITIVE_INFINITY It is greater than any other value, and you can get it by dividing by 0 or by evaluating the express...

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...