C++ :: Including Header And Inheritance - Parent And Child Classes
Jan 27, 2012
I have defined to classes : Parent and Child. I have some global variables in a header file named as "var.h". These variables are used in both Parent and child Classes. The source code of these classes are written below:
Parent.h
==============================================
#ifndef PARENT_H
#define PARENT_H
#pragma once
#include <stdio.h>
class Parent {
[Code] ....
After compiling, the compiler returns a fatal error as follows:
1>Parent.obj : error LNK2005: "int counter" (?counter@@3HA) already defined in Child.obj
1>C:Documents and SettingspishiDesktop estDebug est.exe : fatal error LNK1169: one or more multiply defined symbols found
It says the "counter" is defined multiple times....
I have a main.h file where I include all the needed things to make my program compile properly, string, vector etc.
And I also have another header file which comntains a class that is used later in the code (globally), I decided to keep it in another file to make it more clear and easier.
I need to include that file in main.h, but I also include main.h from that class header file because it contains some other includes that are required to compile.
Is this a good thing? Or should I keep main.h out of that class header file and include just things required for the class?
I may have complicated it too much, so I'll show an example, what I do now:
// ---- main.h ---- #include <string> #include <vector> #include <ctime> // other includes, these are just examples #include "MyClass.h" // the separated class header file
[Code] ......
So, from what you can see MyClass.h requires just including the vector, but to avoid repeating myself I include main.h which does that already, but also includes MyClass.h
So, I have two questions: 1. Is it ok to include in that way (including a file that includes the including file) 2. Is it good to include a main header file with all the includes even if I just need one of them, or should I skip including main.h and include just the things my class requires (vector is just an example)
I want parent and child processes to communicate in C linux using pipes. I have created two file descriptors. one for parent to child i.e. readpipe and other writepipe for viceversa. But I am getting null as output for ch and ch1 strings in my code below.
#include <stdio.h> #include<stdlib.h> #include #include<unistd.h> int main(){ pid_t pid;
I'm using windows forms and I have a parent dialog box that consists of a text box and a drop-down that launches a child dialog box. The child takes user input and then prints dialog to the text box in the parent. However, the output does not appear in the text box until I close the child.
Now my question is, how do I get the text to appear without closing the child? I hit a button to send the info to the text box, but it still doesn't appear until the child closes. I also need to set up a button to suspend the child so that the user can click/copy/etc the parent.
I am making a very basic parent/child class based program that shows polymorphism. It does not compile due to a few syntax errors reading "function call missing argument list. Lines 76 and 77, 81 and 82, and 86 and 87.
#include<iostream> using namespace std; class people { public: virtual void height(double h) = 0; virtual void weight(double w) = 0;
I have a hpp file with a list of inline finctions like this:
Code: inline int check() { return 1; } inline int check_1() { return 1; }
... What I would like to do is to include them into several unrelated classes. How can I do this. Can I just add the hpp inline functions in headers of my class containing files or not. I mean if they are not defined as class functions how can they be called. I don't understan the logic.
I have the header (and accompanying lib file) in my project folder, I have it in my solution explorer. And I've tried to add it via C++ Directories.. but that doesn't seem to exist anymore, instead it points to a user property sheet, but where to find or access it ...
I have two report.h files located in two different directories. However the contents of them are different. How can I include the report.h file located in guarddog into the report.h file located in sky?
I am currently developing a small quick'n dirty SIP (Session Initiation Protocol) parser. Its task is to read a file (or command-line argument) with a SIP requst and parse it using the sofia-sip library. It should exit either with "1" on parsing failure or "0" on parsing success.
I have taken the code snipplet from here: [URL] .... resulting in this source code:
We want a solution in C++ that must be able to do the following:
Given a string of particular type, lets say 'A', we want to find all the types that derives from 'A'.
Instantiate new objects out of the types that are derived from 'A'.
E.g. Lets say we have a class, VehicleEntity. VehicleEntityhas child classes, PassangerCarEntity, TruckEntity, TrainEntity, BoatEntity.
We are unsure what vehicle entities there may be as the a library could be added containing more VehicleEntities. E.g. an AirplaneEntity thaterives from VehicleEntity could be added after deployment.
In the application, when a user wants to select a VehicleEntity, the user should be able to pick any of the entities deriving from VehicleEntity. This includes the PassangerCarEntity, TruckEntity, TrainEntity, BoatEntity and AirplaneEntity. The user selects an Entity, lets say AirplaneEntity, A new object of type AirplaneEntity must be instantiated.
The following is an concept example in C# of what we want to achieve in C++.
In C# the items for the dropdown list can be retrieved as follows:
Type vehicleEntityType = typeof(VehicleEntity); List<Type> types = new List<Type>(); foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies())
[Code] .....
We are aware that standard C++ does not contain any Metadata on its objects, and thus it is not possible without a workaround. It does not seem possible with RTTI and boost.Mirror.
I am currently having an issue with a piece of code that I am writing in which I need to use a vector of a child class as a parameter in a function in the parent class. Below is an example of my code:
#include "child.h" #include <vector> class parent { parent(); function(std::vector<child> children); // rest of class here }
When I do this my program doesn't compile. However if I try to forward declare, as shown in the following example, it once again refuses to compile:
#include <vector> class child; class parent{ parent(); function(std::vector<child> children); // rest of class here }
This time, it refuses to compile because it needs to know the full size of the class child in order to create the vector. How to being able to access the child is essential for my program, so what should I do?
The abstract class can provide more functionality without affecting child classes.If we add any method to the interface ,then will it affect all the child classes ?
I'm trying to print a single linked list backward with functions/classes. I have created the main file and 3 header files. But I'm getting an error on one of the header files, linkedListIterator after adding #include "linkedListType.h". It says that "linkedLlistType.h" is calling itself. And when I try to run it, I get an error of "too many header files." I have tried changing the headers many times, but nothing seems to work.
.cpp file:
/*(Printing a single linked list backward) Include the functions reversePrint and recursiveReversePrint, as discussed in this chapter, in the class linkedListType. Also, write a program function to print a (single) linked list backward. (Use either the class unorderedLinkedList or the class orderedLinkedList to test your function.)*/
When I attempt to compile the above code, I get several thousand errors, mostly "stray ‘@’ in program", coming from the cocoa framework. It compiles and runs correctly if I omit the cocoa include or if I name the file main.mm instead of main.cpp.
I'm pretty sure it's failing because cocoa is written in objective c and I'm reading it as c++ code..how to include an objective c file in a c++ program?
I am trying to include all repetitions for just one turn but I keep getting
00.0 but I want (the one in red) 170.3 0 0.3 180.0 17 0.0 190.3 18 0.0 200.3 19 0.3 210.0 20 0.3 220.0 21 0.0 22 0.0
so basically I call a function that represents just one turn of getting a random number, and then when the player decides he wants to get a random number that is at least 17 and wants to repeat this 3x I have to print out this chart that shows the chances of the player rolling the numbers between 17-22 [how many times does he get 0,17,18,19,20,21,22] this is what I have
cout << "your score: " << (' ') << "chances for that score:" << endl; /* score is the player's total score for the one turn */ int score = 0; int score0 = 0; // 0
I have an array of (Student)classes created in Manager.h, which contains a new instance of class Name (name),(in Student.h)How would I go about accessing the SetFirstName method in Name.cpp if I was in a class Manager.cpp? I have tried using Students[i].name.SetFirstName("name");
// In Manager.h #include"Student.h" class Manager {
I've worked a lot in Java and Perl and now I'm learning C++ and working on a simple e-reader (let's not get into why I'm not just using Kindle or other existing ones). This is for me and a number of friends.
At first my project will be on OS X, then Windows and Linux, and I hope to eventually use it on Android and iOS. I know that the last two will require separate GUIs, but I'm hoping the rest of the code will port easily.
Here's the problem:
I'm using Poppler to read and display PDF files. I started installing it on my iMac and it needs FontConfig, which is turning out to be a difficult install. I would not want to walk others through this or make them have to install Poppler and FontConfig (and any other libraries I find both need).
I thought I could just compile my final binaries using "-static" but I've been reading about how some libraries can't be statically linked or compiled.
Also, since I want to eventually port this to 4 other OSes (and apparently Poppler can work on those target OSes), I don't want to do something now or depend on something that will make it hard or impossible to port to other OSes later.
With that in mind, here are my questions:
1) Why is it some libraries cannot be compiled statically? How do I know if I'm dealing with one of those libraries?
2) Am I right that I could compile this program statically, and the resulting binary would include code from Poppler and FontConfig and other libraries would be included in the resulting executable binary?
3) What do I need to watch for so I can tell if using a particular library will be a problem when I need to port my program to a new OS? (Assuming, of course, that searching shows that library will compile or has been ported to that OS.)
I have four source files. The main source file includes two other source files. The two other source files both include the fourth source file. In the fourth source file I have an include guard. Will the code from the fourth source file exist in two locations in the compiled code? Is this something that is compiler dependent? An example of this is shown in the code below.
I am displaying data from an Excel Spreadsheet through an ASP.net web form using C#. I would like to run an SQL query on the data, but am having trouble figuring out how to use a string in my query.
Here is the code I am running in my .aspx.cs file. I am also using a .aspx to display the data in a GridView.
Ideally, I would like to add a WHERE clause to my string (string sSQL = "SELECT * FROM [Sheet1$A1:D14]"/> in order to query the current month and display the row of said month from the Excel Spreadsheet.
I have attempted to use a DataAdapter to insert the string into the query, but could not figure out how to conform my code to work with it.
