class

问题 I have a few objects I need to perform actions on from different threads in c++. I known it is necessary to lock any variable that may be used by more than one thread at the same time, but what if each thread is accessing (writing to) a different data member of the same object? For example, each thread is calling a different method of the object and none of the methods called modify the same data member. Is it safe as long as I don't access the same data member or do I need to lock the whole

问题 Here's a very simple code I made to demonstrate the problem I'm encountering. What's happening here is that I'm creating two different instances of the same class but changing an attribute of one will change the corresponding attribute of the other instance. I'm not sure why this is. Is this normal in Python or am I encountering something being totally messed up? class exampleClass(object): attribute1=0 attribute2="string" x=exampleClass x.attribute1=20 x.attribute2="Foo" y=exampleClass y

问题 I am building application which needs to have OOP style MySQL query builder. I want to be able to flexibly build complex queries using only PHP and to get resulting query string for execution with my own database driver. Does anyone know of a good standalone query builder for PHP? Please note that I don't need database driver I need bare MySQL query builder class (preferably written with camel style function and variable names). 回答1: Finally I took Doctrine ORM and modified it little bit to

问题 I have been a Python Scientific Programmer for a few years now, and I find myself coming to a sort specific problem as my programs get larger and larger. I am self taught so I have never had any formal training and spent any time really on 'conventions' of coding in Python "properly". Anyways, to the point, I find myself always creating a utils.py file that I store all my defined functions in that my programs use. I then find myself grouping these functions into their respective purposes. One

问题 I have been a Python Scientific Programmer for a few years now, and I find myself coming to a sort specific problem as my programs get larger and larger. I am self taught so I have never had any formal training and spent any time really on 'conventions' of coding in Python "properly". Anyways, to the point, I find myself always creating a utils.py file that I store all my defined functions in that my programs use. I then find myself grouping these functions into their respective purposes. One

问题 I have been a Python Scientific Programmer for a few years now, and I find myself coming to a sort specific problem as my programs get larger and larger. I am self taught so I have never had any formal training and spent any time really on 'conventions' of coding in Python "properly". Anyways, to the point, I find myself always creating a utils.py file that I store all my defined functions in that my programs use. I then find myself grouping these functions into their respective purposes. One

问题 This question already has answers here : How do I clone a generic list in C#? (27 answers) C# Value and Reference types (6 answers) Closed 2 years ago . class ListHolder { public List<char> List; public ListHolder(List<char> l) { this.List = l; } } class Program { static void Main(string[] args) { List<char> a = new List<char>(); a.Add('s'); ListHolder c = new ListHolder(a); a.Clear(); Console.WriteLine(c.List.Count); } } I've put some list into that class, than I cleared the list and wrote

问题 This question already has answers here : How do I clone a generic list in C#? (27 answers) C# Value and Reference types (6 answers) Closed 2 years ago . class ListHolder { public List<char> List; public ListHolder(List<char> l) { this.List = l; } } class Program { static void Main(string[] args) { List<char> a = new List<char>(); a.Add('s'); ListHolder c = new ListHolder(a); a.Clear(); Console.WriteLine(c.List.Count); } } I've put some list into that class, than I cleared the list and wrote

问题 This answer shows how a simple ES6 class: class A { constructor() { this.foo = 42; } bar() { console.log(this.foo); } } is equivalent the following ES5 code: function A() { this.foo = 42; } A.prototype.bar = function() { console.log(this.foo); } Is is similarly possible to translate ES6 class inheritance to ES5 code? What would be the ES5 equivalent to following derived class? class B extends A { constructor() { super(); this.foo2 = 12; } bar() { console.log(this.foo + this.foo2); } baz() {

问题 I have a div, when I clicked on it, should turn all the elements in the .counter class to red, but at the moment it does nothing. I believe you have to run through a loop first and then use this somehow to select all elements in the class width JS? CSS .counter { width: 100px; height:100px; background-color:orange; } #btn { background-color:aqua; width:50px; height:50px; position:absolute; left:200px; top:10px; } HTML <div class="counter"></div> <br> <div class="counter"></div> <br> <div