regarding dynamic vector.
Shape2DLink.cpp
void Shape2DLink::InputSensor()
{
string shape,type;
[Code]....
So i'm actually using polyphormism for calculating the area of the cross and other shapes. so how do I actually make use of dynamically create an object this way?
do I create them in my Shape2DLink or in my individual child classes?
Please consider the following code :
#include <iostream>
using namespace std;
class superclass;
class subclass1;
class subclass2;
[Code] ....
As you can see I want to create a dynamically allocated storage of references to a parent class each of which can then point to a child class, how ever I do not know how to extract the child class out again from that array so i may access its variable b.
I am working on a project that requires me to create objects from a abstract class that has 2 child classes (that need to be derived). Any examples on how to do this? I looked online and the examples were pretty vague. the main error that I am getting is when I make a temp object with & in front of it (such as Employee &genericEmp) it throws a must be initialized error.
View 6 Replies View RelatedHow would I implement a way that i could create as many objects as the user wants?
Let's say every time a user clicks space bar a new cat object would be created, because right now i create lots of objects without initializing and every time i get a input i assign values to the object, the downside is that is limited for the amount of objects i create.
As well i don't want to cause a memory leak, specially in c++ because i need to use the delete keyword.
Project compile successfully but console turn off with "Windows " with error doesn't print or get anything
Code:
#ifndef Point_HPP // anti multiply including gates
#define Point_HPP
#include <string>
#include <iostream>
#include <sstream>
#include <cmath>
[Code] .....
I need to dynamically create a new Memo structure to hold memorized fib #'s.I have two structures:
Code:
typedef struct HugeInteger
{
//array to hold the digits of a huge integer
int *digits;
//number of digits in the huge integer
int length;
}
[code]....
am having trouble with initializing the struct inside of the new Memo, I need the digit fields to null and the length field to 0 to indicate that F[i] has not yet been memoized...I have F->digits and F->length in the for loop but this just simply doesn't work..
I am having some trouble on understanding how to create a dynamically allocated array and then inputting some information in to it from a text file.
Example text file:
John Doe saving 135246978 300 0
Need to create multiple word documents on the run.
My problem is its creating the last one only.
In this book, item 3 is about never treat arrays polymorphically. In the latter part of this item, the author talks about the result of deleting an array of derived class objects through a base class pointer is undefined. What does it mean? I have an example here,
Code:
class B
{
public:
B():_y(1){}
virtual ~B() {
cout<<"~B()"<<endl;
[Code] ....
This sample code does exactly what I want. So does the author mean the way I did is undefined?
Let's say I have a Car object , and it contains inner Engine object.
Code:
struct Car{
Engine mEngine;
};
In order to initialize the engine object NOT by the default constructor (if it has any) , we use initialization semantics:
Code:
Car::Car:
mEngin(arg1,arg2,...)
{
other stuff here
}
Now it gets tricky: Let's say a Car objects has 10 inner objects, each object has about 5 variables in it . Car is a base class for , e.g. , Toyota class. you don't want the Car class to have a constructor with 50 arguments. Can the inner objects of Car be initialized from the base class , e.g. Toyota?
Code:
class Toyota:
Car(...),
mEngine(...),
mGear(..)
{
...
};
The other options are:
1) like said , create a Car constructor which gets 50 arguments, then initialize Car as whole from Toyota - the code becomes less readable and less intuitive
2) Car constructor which get built-objects as arguments and initialize the inner objects with copy constructor . the code gets more readable but then you create many excess objects .
Working on a console application and I am trying to figure out a way that allows users to enter an object property along with a value. For example
class Box{
public:
int height;
int width;
int length;
[Code] .....
For example if a user inputs "height" for Name and "13" as value I would like to find a way to change ab's height to 13. I want to make this work so that one can add another class and get the same functionality.
I tried looking online and I think maps are a way to do this and I tried doing that but I don't know how to proceed after/what code to write that would allow me to change it.
Note: I can't use if else statements or hardcoding to match the input to member as I want to make this extensible.
class Album{
private:
char albumName[100];
Song* List;
int numSongs;
public:
Album(char*);
~Album();
[Code] ....
And everytime I create the class it can have only one song because I set numSongs to zero.
I actually need to create a labyrinth and a player who needs to go thru the map collecting objects (like bags, water etc...). I planned to do the map with a bidimentional array (5x5) but I dont know how to put different objects on an index.. Ex: array[3][2] will have a Botte of water and an energy bar..
Someone told me to use structs but I dont really understand how this would work... I've tried so many times bit I cant do it...
I'm trying to create an inventory system in C++ using classes and objects. Here is what I have now
Item.h
#pragma once
#include <iostream>
#include <allegro5/allegro.h>
#include <allegro5/allegro_image.h>
[Code]....
Basically what I want my inventory system to become is this: [URL] Each slot can hold an item.
Basically this inventory system should be able to do what RS Inventory system can do. (Hold items, Use items, Equip Items (No need for moving item))
well i create a State.h class
#ifndef STATE.H
#define STATE_H
class State {
public:
virtual void handle_action() = 0;
virtual void update() = 0;
virtual void render() = 0;
};
#endif //STATE.H
What i'm trying to create is a simple State Manager for SFML! I created another class that inherits State.
#pragma once
#include "state.h"
class FirstState : public State {
public:
FirstState();
~FirstState();
void handle_action();
void update();
void render();
};
So the question is this, each state that i have will inherit the State class. However, i wanted to perhaps add each state object into a vector array. But i'm not sure as to what data type it be? I have a state manager class that will contain the vector.
What i want to do is this, each game state will create an object that will inherit functions from the state.h class. I want to store them all in a vector array, but each object is clearly named different. My curiosity was wondering, since all those different states inherit the State.h class, can i simply create a State Object std::vector<State> *states; that will contain all those different state objects?
[URL]....
Im supposed to create an array of eight Circle objects initialized with the radii which is in the program. Also I must use bubble sort to arrange the objects is ascending order.
ERRORS:
'initializing' : cannot convert from 'double' to 'Circle'
'setRadius' : is not a member of 'Circle'
see declaration of 'Circle'
'findArea' : is not a member of 'Circle'
see declaration of 'Circle
#include "stdafx.h"
#include <iostream>
#include <iomanip>
using namespace std;
class Circle {
[Code] ....
class FlashCard {
public:
int a,b;
void PrintCard(void);
int CorrectAnswer(void);
};
void SwapFlashCard(FlashCard &a,FlashCard &b)
[Code]....
Why does Xode warn me that Type'FlashCard'does not provide a subscript operator on line 22,23,29 and 30?
I have been working on an assignment where I have to add three objects of a class Matrix. The class should have the flexibility to add more than two oprands without changing any operand on Left hand side of the '=' operator.
Matrix obj1, obj2, obj3, obj4
Obj1=obj2+obj3+obj4
I am using the following code for this
Matrix Matrix::operator + (Matrix &obj) {
if((this->Columns == obj.Columns) && (this->Rows == obj.Rows)) {
for(int i=0;i<obj.Rows;i++)
[Code] .....
the problem is that it is just adding only 2 operands. How can I add more?
I need an array of class objects but am unsure of how one might accomplish this. I have so far...
//element class driver code
Element Arsenic(lowCeiling, highCeiling);
Element Cadmium(lowCeiling, highCeiling);
Element Chromium(lowCeiling, highCeiling);
Element Copper(lowCeiling, highCeiling);
Element Lead(lowCeiling, highCeiling);
Element Nickel(lowCeiling, highCeiling);
Element Molybdenum(lowCeiling, highCeiling);
Element Mercury(lowCeiling, highCeiling);
Element Selenium(lowCeiling, highCeiling);
Element Zinc(lowCeiling, highCeiling);
Element metal[10] = {Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Molybdenum, Mercury, Selenium, Zinc};
Could the array be created in this manner or is that illegal code?
So I'm trying to store class objects in a vector:
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
[Code]....
1. Am I storing it correctly?
2. How would I access the stored data, say, if I wanted to compare it to other stored data or COUT it?
My thought is that I would need to establish a variable for the class in the header and call the class within the .cpp file
//class A.h
B b;
Then in class A, to create the object and use a method from the object I would -
//class A.cpp
A::A(){
b();
}
int someAmethod(){
b.bmethod();
}
What I want to do is have an admin class which will hold all the employee objects, can add them, list and calculate salaries. I'm trying to make array of objects, not sure if it's right
here is the code
Code: #include <iostream>
#include <string>
using namespace std;
class Employee {
public:
Employee(string name, short type, int salary)
[Code] .....
For a beginners C++ lab, I have a base class Employee and two derived classes HourlyEmployee and SalaryEmployee. In main, I have a vector defined as vector <Employee *> VEmp; It's then passed to a function to get the input, which works fine. But what I'm struggling with is another function with the header "printList(const vector <Employee *> & Ve)". It's supposed to loop through the vector and call the appropriate printPay function, which is a seperate print function inside each derived class. How do I loop through the vector and print it out? I was trying to do a for loop and something like "Ve[i].printPay();", but that doesn't work. So how would I do it?
Here's some snippets of the relevant code.
class Employee {
....
virtual void printPay() = 0;
};
class HourlyEmployee : public Employee {
[Code] ....
For example when I have:
Class A{
B objectB;
};
Now when I instantiate the object of class A like:
main(){
A objectA;//option 1
A* pObjectA = new A();// option2
}
How is objectB stored in memory (stack heap etc.) for both options??
i ran the following code in the latest version of code::blocks and it tells me that the objects cout and cin are not declared in this scope. what is the problem?
I used to use Turbo C++ 3.0 and i had no problem whatsoever with that compiler. But now i am trying to move to code::blocks but it is proving very very hard as all the standards have been changed.
I am a school student and thus, we had been told to practice on Turbo C++ 3.0 and now i am unable to unlearn it. Also, if i use printf in place of cout there is no error but i want to use cout as it is what i am comfortable working with.
#include<fstream>
#include<conio.h>
int main() {
using namespace std;
char name[20];
[Code] ....
Is there some document to which i can refer so as to get the latest C++ standards which is C++0x i believe?
Is dere is any limit in number of objects of a class?
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