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Below code is dealing with a TYPE* const pointer. struct D { void Check () { D* const p = new D; // 2nd test is "p = 0;" cout<<"p = "<<p<<endl; (D*&)p = new D; cout<<"p = "<<p<<endl; // prints 0, "p = 0;" at declaration } }; int main () { D o; o.Check(); } My questions are, If you initialize with 0 , then even though typecasting next time will not work. Is doing such typecasting is undefined behavior ? this pointer is also of TYPE* const type, then why compiler doesn't allow the same operation for this ? As others have said, this is undefined behaviour since it attempts to modify a const

I am trying to understand the this keyword on Javascript . I was doing some tests on chrome console and I came across two different results that I was expecting to be the same: var myTest = {}; myTest.test1 = function() { return this; // this = Object } This first function returns myTest object which I understand. var myTest = {}; myTest.test1 = function() { return function test2() { return this; // this = Window } } Why is the second function returning the window instead of the myTest object? Thank you this refers to the current object on which the function is called. When you called test1 ,

In the snippet below I use $(this) to refer to the element in which the function is being called from. I know it is not correct because I printed out the values and it gave me 'undefined'. How do I refer to the input element? $(function() { $( ".datepicker" ).datepicker({ onSelect: function (date, obj){ if(confirm('Is this correct?: '+ date )) { $.post('edit.php', { "row": $(this).data('id'), "date":date, "field":$(this).name, "ajax":'true' }); } } }); }); Here is the html element: <input name="appvAcadVp" data-id="someid" class="datepicker" size="10" type="text" placeholder="someholder" >

In the traverse npm package there's this example var obj = [ 5, 6, -3, [ 7, 8, -2, 1 ], { f : 10, g : -13 } ]; traverse(obj).forEach(function (x) { if (x < 0) this.update(x + 128); }); Inside the callback function you can call this.update . I know in these kinds of cases you should use the regular (not ES6 arrow) style of function definitions like shown above. But out of curiosity, how would you make that code work with ES6 arrow function syntax? If I try as follows I get TypeError: Cannot read property 'update' of undefined because of course this is not the same as above. traverse(obj)

As I continue to try and improve myself as a junior PHP developer, I have started to try break down other peoples work. I find it helps me understand, as well as giving me ideas. Two things I do not get, in a PHP class, what $this means, and what array($this,'some_function') means when I would expect a function name in it's place. Many thanks Gordon Please see the PHP Manual on Classes and Objects . $this refers to the object instance. Also see these questions: What does the variable $this mean in PHP? What is the meaning of $this For array($this,'some_function') see the PHP manual on

there is two type of scope in javascript named function scope global scope now i am executing this code function abc() { alert(this); } abc(); abc call returning me [object Window] Why?? function makes another scope so why it is representing window this , inside any function, will be the object on which the function is invoked. In your case, you are not invoking it on any object. So, by default this refer to global object, in your browser, it is the window object. But in strict mode, if you invoke it like this, this will be undefined . "use strict"; function abc() { console.log(this); //