constructor

问题 I'm having some trouble getting my copy constructor to work in my BigInt class I'm working on. In BigIntVector.cpp in the copy constructor, the lines: for (int i = 0; i < vectorSize; i++) { vectorArray[i] = orig.vectorArray[i]; } causes the exception 0xC0000005: Access violation writing location 0x00000000. Any help figuring out why would be appreciated. Thank you. In BigInt.cpp : // copy constructor BigInt::BigInt(BigInt const& orig) : isPositive(orig.isPositive) , base(orig.base) , skip

问题 I'm new to Java, so I'm sure this is an easy question (my head is spinning from studying all day long). Here's the code I'm studying and can't remember/figure out what this line of code is doing: public Temperature(String type, double degrees) { if (type.equalsIgnoreCase("C")) Is this considered a constructor? What are the two parameters "String type, double degrees" doing? tia. Here's the code from the top down: public class Temperature { private double degreesFahrenheit; // Fahrenheit

问题 How can I copy an object containing an array of other objects? Here is my copy constructor: public university(university univ) { String name1=univ.getname(); int numOfPublications1=univ.getnumOfPublications(); Department[] depts1 =new Department[numOfDepts]; depts1=univ.getdepts(); } This is not working because the array is not there. 回答1: Try doing this. public university(university univ) { String name1=univ.getname(); int numOfPublications1=univ.getnumOfPublications(); Department[] depts1

问题 [Summary] I have an Invoice form with several private TextBoxes in my C# program. When the user changes the text of those textboxes, the search form appears. I would like to transfer some values from my dataGridView(which is linked to my database) in the search form to those TextBoxes in the Invoice form (when I press Enter for example). [Description] In my Invoice form I have merchendise code textbox and merchandise name text box. When the user changes the text of those textboxes, the search

问题 I want to know that why i have to define an explict constructor because i am getting error which says that default constructor cannot handle exception type Exception thrown by implicit super constructor. class A { A() throws Exception { System.out.println("A Class"); } } public class Example extends A { public static void main(String args[]) throws Exception { Example t = new Example(); } } 回答1: Yes - your Example class is effectively declaring: public Example() { super(); } That won't

问题 I installed visual c++ November 2012 CTP but it seems i do something wrong because i still can't use delegating constructors I set the Platform Toolset to : Microsoft Visual C++ Compiler Nov 2012 CTP (v120_CTP_Nov2012) This is my code: #pragma once #include<string> class Hero { private: long id; std::string name; int level; static long currentId; Hero(const Hero &hero); //disable copy constructor Hero& operator =(const Hero &hero); //disable assign operator public: Hero(); Hero(std::string

问题 I am currently trying to get deeper into the .NET framework. I ran across an error while I was wondering if I could create two CommandManagers: Cannot create an instance of CommandManager because it has no public constructors. Obviously it means: don't do it, and it might not even make sense to have two of them. Now I came across an other error before with the message: Cannot create an instance of ... because it is sealed The effect is the same in prohibiting but what is the difference. Why

问题 I have a class method in a category to construct a Cocoa collection in some way that the built-in initializers don't allow. Due to the limited initializer functionality, I have to use the mutable version of the collection to actually build it. Here's an example for NS{Mutable}IndexSet : @implementation NSIndexSet (WSSNonContiguous) + (instancetype)WSSIndexSetFromMask:(NSUInteger)mask { NSMutableIndexSet * set = [NSMutableIndexSet indexSet]; for( NSUInteger i = 0; i < (sizeof(NSUInteger) * 8);

问题 Do fields need to be initialized using the constructor for angular components? A lot of angular tutorials do: counter: number; constructor() { this.counter = 1; } Instead of just counter: number = 1 . 回答1: Both are correct programming wise, Initialized within the constructor It would be good practice to initialized within the constructor , it's kind of code separation of declaration + initialization . That will increase your code readability and you will be sure that all values initialized

问题 struct Foo {}; struct Bar : Foo {}; Foo &foo = Bar; // without () I wonder, Is it a legal notation? And if it is legal, could you give some details? Something like, Why it's legal? Or, What is the origin of such a notation? EDIT: I cannot compile this code. But I met a code like that and wanted to know whether such a notation is allowed (probably just my compiler doesn't support this notation). I'm having some uncertainty since the following notation is quite legal: Foo *pFoo = new Bar; 回答1: