constructor

问题 Update: Since this is unanswered, I'm changing the question slightly. Comments on the post on Dean's blog linked below indicate this technique does not work in Safari. My question now is: does the technique described below work* in modern browsers, and in particular can someone confirm whether it works in Safari? Here's a more recent blog post. It says at one point: Sandboxed natives ... are supported in a variety of browsers, including ... Safari 2.0+ ...but later says that the iframe

问题 I'm creating a custom vector class for a school project and I'd like to be able to initialize it like this: vector x = { 2, 3, 4, 5 }; Is there any way to do this is C++? Here is the header of my class: class vector { private: int vsize; int valloc; double* values; public: vector() : vsize(0), valloc(0), values(nullptr) {} vector(???); vector(const vector& v); int size() const { return vsize; }; int alloc() const { return valloc; }; void resize(int newsize); void insert(double x); void insert

问题 I'm creating a custom vector class for a school project and I'd like to be able to initialize it like this: vector x = { 2, 3, 4, 5 }; Is there any way to do this is C++? Here is the header of my class: class vector { private: int vsize; int valloc; double* values; public: vector() : vsize(0), valloc(0), values(nullptr) {} vector(???); vector(const vector& v); int size() const { return vsize; }; int alloc() const { return valloc; }; void resize(int newsize); void insert(double x); void insert

问题 I am having trouble understanding the part inside the curly braces. Array.new(10) { |e| e = e * 2 } # => [0, 2, 4, 6, 8, 10, 12, 14, 16, 18] I get that a new array with ten values is created, but what is the second half doing? 回答1: Let's go over this in details: nums = Array.new(10) This creates a new array with 10 elements. For each array element it passes control to the block specified by: { |e| e = e * 2 } The |e| represents the element's index. The index is the position in the array. This

问题 I am using a third party library class XYZ as an argument in my model. XYZ does not have a default constructor. So spring is not able to create bean for it giving error message as org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.data.mapping.model.MappingInstantiationException: Could not instantiate bean class [org.abc.def.XYZ]: No default constructor found;nested exception is java.lang.NoSuchMethodException: org.abc.def

问题 public partial class Form1 : Form { Class1 class = new Class1(30,a); public Form1() { InitializeComponent(); } public int a = 0; private void Timer1_Tick(object sender, EventArgs e) { a += 1; } } I want to use the variable 'a' in my calss but i cant get "move" it over to my class via the constructor i'm using. The error message i recive is : Error: A field initializer cannot reference the non-static field, method, or property. I know it's a basic problem but help is appreciated class Class1 {

问题 in this question: template; Point<2, double>; Point<3, double> Dennis and Michael noticed the unreasonable foolishly implemented constructor. They were right, I didn't consider this at that moment. But I found out that a constructor does not help very much for a template class like this one, instead a function is here much more convenient and safe namespace point { template < unsigned int dims, typename T > struct Point { T X[ dims ]; std::string str() { std::stringstream s; s << "{"; for (

问题 I've created an example to illustrate: // this is the parent class function animal() { console.log('animal constructor') } // allow animals to walk animal.prototype.walk = function() { console.log('animal walking') } // create child class function cat() { console.log('cat constructor') } // cat inherits from animal cat.prototype = Object.create(animal.prototype); // let cats meow cat.prototype.meow = function() { console.log('meow') } // create a cat object var myCat = new cat(); /* output:

问题 I have tried to find a lot that what if only one class is made virtual in multiple inheritance ? The behaviour of constructor call is not clear to me in this case. Let say for example code- #include<iostream> using namespace std; class grand{ public: grand(){cout<<"grandfather"<<endl;} }; class parent1:virtual public grand{ //virtual used only here public: parent1(){cout<<"parent1 "<<endl;} }; class parent2: public grand{ public: parent2(){cout<<"parent2"<<endl;} }; class child:public parent1

问题 Will the destructor of the base class be called if an object throws an exception in the constructor? 回答1: If an exception is thrown during construction, all previously constructed sub-objects will be properly destroyed. The following program proves that the base is definitely destroyed: struct Base { ~Base() { std::cout << "destroying base\n"; } }; struct Derived : Base { Derived() { std::cout << "throwing in derived constructor\n"; throw "ooops..."; } }; int main() { try { Derived x; } catch