Code:
public class ColorGenetics
{
public static hk1Class jw;
public static linkedClass link;
}
[code]...
Code builds fine but compiler says I tried to use bject link w/o providing an instance. Class linkedClass has an instance of Class hk1Class set to var jw1.I had linkedClass useing the same var jw for the object instance. I changed it to jw1 thinking that would clear it up and it didn't.
I have a method to take a Tile object and make an instances of it based on some data from the original object. Than it is suppose to manipulate the a specific instance and save the results. The first loop through it works but it changes all instance as well as the base.
public static int recurse(int count, Tile[,] b,Huristic h,int check) {
if (check==1) {
boardState.Add(B)/>;
return check;
} if (check == 0)
[Code] .....
I am trying to use web api in order to return custom json response keys. For this i have return a custom class to return json response
Custom Class:
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
[Code].....
I have a combobox with Items 1024
2048
4096
8192
String cach = form.comboCache.SelectedItem.ToString();
I am using the above code to retrive an item selected by user,But this line is giving an exception "Null Reference Exception, Object reference not set to an instance of an object"
I am using session to pass object from controller to custom class in MVC Web API. here is my code, i am getting error at session.
public HttpResponseMessage Get()
{
var person = db.Persons.ToList();
[Code]....
I need to send same instance of object of a class in two function (Main function and thread function). The class is something like this:
//The class need to have constructor.
Class ABC {
public:
DWORD *IdG;
ABC(int number) {
IdG = new DWORD[number];
}
}obj(32);
The obj(32) is called in following two function. Function F1 is called using thread in main function.
void F1() {
obj.test;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
obj.test1;
_beginthread(F1,0,(void*)number);
}
The code works well when the object of class ABC is created as shown above. My problem is the value that is passed in the object ('32') is to be read from the file.
If I read the file and create object separately in Main function and function 'F1' then , function 'F1' is not executed.
How to create same instance of object for Main function and function 'F1' with value passed in the object taken from the file.
I am new to C++. I am trying to create 5 instance object of class Test. I wonder if these two codes are the same.
Test testArray[5];
//which one is the correct way or what is the correct way?
for(i=0;i<5;i++)
{
Test testArray;
}
I'm new in object oriented programming. I need creating a global object/instance of a class, that can be used by any function.
View 19 Replies View RelatedIf I have a class object and multiple vectors, how do I make sure I store the same instance of that object in both vectors? For instance:
Object object;
std::vector<Object> vectorOne;
std::vector<Object> vectorTwo;
vectorOne.push_back(object);
vectorTwo.push_back(object);
Are the objects in both vectors the same instance of the object? Like if I called vectorOne[0].setValue(somethingDifferent); would the value be changed for the object in both vectorOne and vectorTwo? If not, how do I make sure that I only have one instance of the object I'm trying to store in multiple vectors?
Let's say I reference a dll in my project that has an abstract class in it:
public abstract class Module {
public string type;
public abstract string doSomething();
}
And then I have an Assembly object, loaded from a dll that is not referenced in project, but rather loaded during run-time, containing:
public class Tester : Module
{
public static string type = "Test";
public override void doSomething() {
//Stuff being done
return "hello";
}
}
How can I get the value of "type" in the class that is loaded during runtime? How do I use the "doSomething" method of it and get the returned object?
I'm trying to make a "Rain" application, by drawing some lines on the form, and then they must fall. So here is my start code:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
}
Random r = new Random();
Graphics paper;
Line line;
[Code] ....
So when I start debugging I get the "Object reference not set to an instance of an object." error. If I remove the comments lines at "timer1_Tick" this error doesn't appear of course. What can I do to escape from this because it follows me everywhere I go />. I tried to make with arrays, but same problem.
I have this class:
class Excuse
{...
public string Description { get; set; }
public string Results { get; set; }
public DateTime LastUsed { get; set; }
public string ExcusePath { get; set; }
....}
[Code] ...
When I run it, I do get the messagebox popping up with the correct description, but then nothing happens. When I debug, I see the fields under the UpdateForm() method are set to null.
I'm guessing this happening because it is looking at the 'currentExcuse' that was declared in the form body. I thought however that redeclaring 'currentExcuse' in the method would overwrite this instance or am I wrong?
Do I need an array to make this work?
I have built LOG4CXX lib and DLL and trying to use it in my application
Loh.h
class Log
{
public:
[Code].....
In my main I am initializing Log class object and calling Debug method to log debug message to a file.
Issue I am facing is at if(CLogger::oLogger != NULL) which is always returning oLogger as NULL.
Say I have an object and 10 pointers to it in several other objects of varying class types. if the object gets deleted, those pointers have to be set to null. normally I would interconnect the object's class with the classes which have pointers to it so that it can notify them it is being deleted, and they can set their pointers to null. but this also has the burden that the classes must also notify the object when THEY are deleted since the object will need a pointer to them as well. That way the object doesn't call dereference a dangling pointer when it destructs and attempts to notify the others.
Auto pointers and shared pointers are not what I'm looking for - auto pointers delete their object when they destruct, and shared pointers do the same when no more shared pointers are pointing to it. What I'm looking for is a slick method for setting all pointers to an object to null when the object destructs.
lets say I have a pointer p_unit of type c_unit* (c_unit is an a.b.c.)
I have a function that returns a pointer to a new c_unit object:
c_unit * man_add_unit() {
c_unit * local_p_unit;
unsigned short int local_run_code;
print_man_add_menu();
local_run_code = get_a_run_code(); // this bit just gets user input
switch (local_run_code)
[code]....
I assign that to p_unit, then add it to a vector v_units:
p_unit = man_add_unit();
v_units.push_back(p_unit);
cout << "New unit added.
";
The whole program runs on a loop, and another thing the user can do is to print out data on c_unit objects pointed to by v_units. The problem is, in that function up there ^ I give the user the option to go back to main menu without creating a unit.
Since "local_p_unit" is declared but not assigned an initial value, I'm guessing the function would return a "null" pointer (which is what's hanging me up). If I just let this run with the above code, and go to print out the unit data, the program crashes.
I tried to make an if thing with p_unit == 0 but this always returns false and doesn't catch the "bad" unit that will subsequently cause a crash.
Btw, I have considered assigning a reference to a generic c_unit object to that there local_p_unit so it won't return null, then remove pointers to that object from v_units at the end of the loop.. But I know there's got to be a better way.
[URL] ....
Which object's draw is being called?
I am looking at one of the functions of an exercise:
void escape(char * s, char * t) {
int i, j;
i = j = 0;
while ( t[i] ) {
/* Translate the special character, if we have one */
switch( t[i] ) {
[code]...
Notice the while loop evaluates the current value in t to true or false. When we hit the null terminator, does that get evaluated as 0 and hence evaluates as a falsy value so the while loop exits?
When you login to my site my loginservice which is done by ajax and json make a session called context.Session["Name"]. With BreakPoints it shows that everything is good and the variables are in place. However when I use Session["Name"] it comes out as null.
I will add my code at the bottem not
using System;
using System.Collections.Generic;
using System.Linq;
[Code].....
Code:
class BoundingBoxTest : public DemoApplication {
public:
#ifdef DYNAMIC_CHARACTER_CONTROLLER
btCharacterControllerInterface* m_character;
[Code] ....
I am creating the object by calling : BoundingBoxTest::Create();
Do I make a getter to retrieve the demo object or do I build on the Create() method... So that it will return the instance if it is not null. and creates one if there is none?
will copy constructor does object initialization using another already created object? I understand that it can be applied for object initialization and not for assignment.Is it correct?
View 10 Replies View Related#include "B.h"
class A {
public :
A()
{
s_b = new B();
b = new B();
[Code] ....
In my project i have seen static object as above . But not able to know what is the exact use of it and how they are different from general object .
I'm currently learning the Qt framework and doing my first tutorial. Straight away I saw something that baffled me:
notepad.h
Code: namespace Ui {
class Notepad;
}
class Notepad : public QMainWindow
[Code] ....
Note the ui pointer and the heap allocation in the class constructor; I can't wrap my head around why one would do this. What's going on here?
I am putting a instance o the Vehicle Class inside the constructor of the Calculate Class then calling it later. I get a warning saying the variable is not used and a error when I try to used the functions from the vehicle class saying use of undeclared identifier.
Code:
#include <iostream>
#include "Calculate.h"
#include "Vehicle.h"
#include <fstream>
Calculate::Calculate(){
[Code] ....
can i have 1 static variable with instance different value?
View 3 Replies View RelatedOkay so I have a class Student, which takes a number and a vector as a parameter for the constructor. Everything works well, until I output the values of the vector for every instance. The problem is that the same vector is being shared with EVERY instance I create, but I want it to be unique for every single one!
//Student.h
#ifndef __Grade_calculator__Student__
#define __Grade_calculator__Student__
#include <iostream>
[Code].....
I was wondering if (in C++) you can instantiate a class (class foo) then have said class return the already instantiated object. (foo::instance())
In other words, can I have a class return it's-self via it's own methods? I want to be able to create a class (i.e. class foo) early in my program so it is already setup and ready to go. Then, farther down the line, I want to be able to call functions from that class without having to pass that object as an argument to my calling function. Can I do something like so:
MyClass::ReturnSelf()->foo();
or
MyClass::ReturnSelf().foo();