this

what does “this” keyword mean in the initializer block? [duplicate]

。_饼干妹妹 提交于 2019-12-01 04:47:47
This question already has an answer here: In Java, what is the difference between this.method() and method()? 9 answers What does “this” mean? [duplicate] 6 answers Here is my code: class StaticBlock { { println("initializer block : " + message); } public StaticBlock(String message) { this.message = message; } private String message; } Now the issue is that, in the initializer block { println("initializer block : " + message); } if I add the this keyword before message , it works, but there is an error when missing this keyword. And the compiler says: StaticBlockDemo.java:34: illegal forward

why the code this point to window object?

你说的曾经没有我的故事 提交于 2019-12-01 04:20:34
问题 my code is: var length = 20; function fn(){ console.log(this.length); } var o = { length:10, e:function (fn){ fn(); arguments[0](); } } o.e(fn); the output is 20,1 ,who can tell me why? 回答1: When the this keyword occurs inside a function, its value depends on how the function is called . In your case, fn() is called without providing the a this value, so the default value is window . With arguments[0]() , the context is the arguments object, whose length is 1 . The point is it does not matter

Is it bad to have the same name for parameter as for member variable? [duplicate]

陌路散爱 提交于 2019-12-01 04:16:19
This question already has an answer here: Should I use the same name for a member variable and a function parameter in C++ 9 answers For example, is this any of the following Bad practice Unreadable Inefficient (the call to this pointer) Any other reason why it's bad to do this . class Person { public: string name; Person(string name) { this->name = name; } }; P.S. How about Person(string name) : name(name) { } The only issue (not a real issue) I can think of is that you can't distinguish member variable with local variable or function parameter . It's just coding style, it's nothing to do

virtual method table for multiple-inheritance

六眼飞鱼酱① 提交于 2019-12-01 04:06:58
I'm reading this article " Virtual method table " Example in the above article: class B1 { public: void f0() {} virtual void f1() {} int int_in_b1; }; class B2 { public: virtual void f2() {} int int_in_b2; }; class D : public B1, public B2 { public: void d() {} void f2() {} // override B2::f2() int int_in_d; }; B2 *b2 = new B2(); D *d = new D(); In the article, the author introduces that the memory layout of object d is like this: d: D* d--> +0: pointer to virtual method table of D (for B1) +4: value of int_in_b1 B2* b2--> +8: pointer to virtual method table of D (for B2) +12: value of int_in

how to get actual content of an object after being replaceWith('something') in jquery

心已入冬 提交于 2019-12-01 03:11:05
I have this code $(document).ready(function(){ $('.selector').click(function(){ obj = $(this); obj.replaceWith('<div class="size">whats up man ??!</div>'); alert(obj.html()); }); }); I want to get the new content of 'obj' that has been 'replaceWith' but, I get the old content instead ... how do I get the actual content of 'obj' ??? my intention is to access the new 'obj' $('.selector').click(function(){ var obj = $(this), repl = $('<div class="size">whats up man ??! <span class="medium"></span></div>'); obj.replaceWith(repl); alert(obj.find('span').attr('class')); //this will print 'undefined'

what does “this” keyword mean in the initializer block? [duplicate]

為{幸葍}努か 提交于 2019-12-01 02:55:38
问题 This question already has answers here : In Java, what is the difference between this.method() and method()? (9 answers) What does “this” mean? [duplicate] (6 answers) Closed 5 years ago . Here is my code: class StaticBlock { { println("initializer block : " + message); } public StaticBlock(String message) { this.message = message; } private String message; } Now the issue is that, in the initializer block { println("initializer block : " + message); } if I add the this keyword before message

Javascript 'this' overwriting in Z combinator and every other recursive function

£可爱£侵袭症+ 提交于 2019-12-01 01:42:38
Background: I have a recursive function implemented by a Z-combinator as is shown here and here so it makes no use of arguments.callee since it will be deprecated in upcoming ES6 . Issue The main issue with the Z-combinator and all recursive anonymous functions I've seen so far is that they updates de this value to the inner function scope (the self-returned at the return clause), so the this that references the top level is lost, and I want to maintain it through all the inner functions. Is there a way to maintain the top level this without passing it as an additional function argument, which

Is it bad to have the same name for parameter as for member variable? [duplicate]

拈花ヽ惹草 提交于 2019-12-01 01:35:25
问题 This question already has answers here : Should I use the same name for a member variable and a function parameter in C++ (9 answers) Closed 6 years ago . For example, is this any of the following Bad practice Unreadable Inefficient (the call to this pointer) Any other reason why it's bad to do this . class Person { public: string name; Person(string name) { this->name = name; } }; P.S. How about Person(string name) : name(name) { } 回答1: The only issue (not a real issue) I can think of is

jQuery looping .fadeIn and .fadeOut of p tags within div one at a time

*爱你&永不变心* 提交于 2019-12-01 00:17:20
The code below successfully fades in one testimonial for 6 seconds, waits 3 seconds, and then fades it out and moves on to the next. Once it reaches the third testimonial it jumps back to the first. This is exactly what I want but on my actual site I have more than three testimonials and in the future may be adding more. I don't want to have to go back and add a new function every time I add a new testimonial. I tried for some time to get this to work using "this" and .next() but failed. I'm hoping someone could make this much more efficient by looping it and getting it to move to the next p

difference between static_cast<const A>(*this) and static_cast<const A&>(*this)

旧城冷巷雨未停 提交于 2019-11-30 23:46:02
in the following code ( taken from effective C++ ): class A { .... char& operator[](std::size_t position) // now just calls const op[] { return const_cast<char&>( // cast away const on op[]'s return type; static_cast<const TextBlock&>(*this) // add const to *this's type; [position] // call const version of op[] ); } const char& operator[](int index) const { ... } } //complete example, tested with VC 2010 #include<iostream> #include<string> class TextBlock { public: TextBlock(std::string st):text(st){}; TextBlock(char* cstr): text(cstr){}; TextBlock(const TextBlock& r) { std::cout<<"copy