C++ :: How To Declare Empty Method
Oct 11, 2013
It has been a few years since I have had to do this, but I need to declare a method in my base class, but produce no code for it. Then when this library is used by my second project I will derive a class from this base class and put the code into it there. How is this possible? I used to know how but do not remember how now.
The library is a static library designed for linking with both 32bit and 64bit Windows applications to handle a lot of the tedious stuff with Windows programming. The method in question handles specific command inputs. However, since each program that uses this library will have different uses for these commands, I want to leave it up to the user to code their own handling, but require it to be coded in the derived class.
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Dec 10, 2014
I have two classes, one class requests another class to populate a vector with some data using getAvailableStreams() method:
vector<AutoRefPtr<ManifestStream> > availableStreams;
std::cout << "now asking for streams." << std::endl;
manifest->getAvailableStreams(&availableStreams);
std::cout << "got so many streams: " << availableStreams.size() << std::endl;
The other class passes another pre-populated vector back:
virtual RESULT getAvailableStreams(std::vector< AutoRefPtr<ManifestStream> >* availableStreams) {
availableStreams = static_cast<std::vector< AutoRefPtr<ManifestStream> >* >(myStreams); //myStreams contains 1 stream
I'm also adding a stream here directly just for testing purposes:
ManifestStream stream2;
availableStreams->push_back(AutoRefPtr<ManifestStream>(&stream2));
std::cout << "calling getAvailableStreams. Giving so many streams: " << myStreams->size() << ", " <<
availableStreams->size() << std::endl;
return result_OK;
}
If I run the code, I can see the following logs:
Now asking for streams. Calling getAvailableStreams.
Giving so many streams: 2, 2
got so many streams: 0
Why am I getting 0 streams when I exist the method? I just had 2 streams in availableStreams while I was inside the method, where have they disappeared?
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Jan 17, 2013
I've been trying for more than one month to access a method found in a library called libcocosnas_static.a. I'm using Cocos2d-X version 2.0.4. The library has been used many times by my company to make games using cocos2d-1.0.1-x-0.12.0 without any problem.
This is what I've done:
1- I added the include paths of the library to both eclipse and Android.mk
2- Included the .h file using #include "NASPlatformUtil.h"
3- Added the libcocosnas_static.a file to the proj.androidobjlocalarmeabi folder
4- Added "LOCAL_WHOLE_STATIC_LIBRARIES += cocosnas_static" to the Android.mk file
5- Called the function using: NASPlatformUtil:: openUrl("http://xxx.xxx.com/");
I can right click on the function, click Open Declaration and get it without any problem, but the compiler keeps on giving me that dreaded error...
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Feb 2, 2015
I have a question similar to the one here: [URL] .....
The main difference is I would like to pass a method of derived class as a parameter to some other method in its template base class.
template <typename BaseType>
class Base {
public:
typedef void (Base::*Callback)(int A);
[Code] .....
The above is an example which does not compile. My compiler complains that the two BaseMethod() calls in DerivedMethod() are invalid uses of non-static member function.
Is this not possible to do, or is my syntax simply wrong? All I want is to be able to pass as an an argument to a method in the base class from the derived class some callback as a variable for the base class to invoke later.
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Jul 22, 2013
A file is created but its empty. And when I first create an entry and then display all the entries, it does nothing.
#include<iostream>
#include<fstream>
#include<iomanip>
#include<string>
using namespace std;
class comp {
[Code] ....
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Jun 30, 2014
We have been assigned to create an iTunes library. Everything compiles in my other .h file but my main is not happy with my object declaration. It keeps stating "primary expression before '{'". Here is my main code:
#include<iostream>
#include<string>
#include<fstream>
#include"myTunes.h"
using namespace std;
//function protocols
void read(string);
[Code] ......
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May 4, 2013
This code:
#include <iostream>
class Foo {
};
int main() {
Foo foo;
std::cout << sizeof ( foo ) << std::endl;
std::cin.get();
return ( 0 );
}
produces this result: 1
Why is the size of an instance of Foo 1, although it doesn't have any member variables?
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Feb 18, 2013
what is the empty state of queue?
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Apr 2, 2014
So this is my working code with sql i want convert it so i can read it from xml, basiccl i need to fill empty list with xml column BrivDat..
var connStr = @"Data Source=(LocalDB)v11.0;" +
@"AttachDbFilename=C:dbaseAdaPlus.mdf;Integrated Security=True";
List<DateTime> Holidays = new List<DateTime>();
using (SqlConnection conn = new SqlConnection(connStr))
using (SqlCommand cmdd = new SqlCommand("select * from Brivdienas", conn))
[Code] ......
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Nov 8, 2014
I have a doubt related Size of empty structure. I know the answer of empty structure is "0".
How and why the Result got ZERO..??
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Mar 13, 2013
I am writing a c++ program in Linux.. I am reading a line from commandline at run time using "getline(std::cin,str);". now, what i want is if i left the commandline as idle (terminal as idle), then i want to know that the commandline is empty... is it possible ???
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Apr 3, 2014
So I was wondering if I were to empty the elements of a stack into a queue, but i only wanted to empty the even numbers or the odd ones. What would the if statement be to accomplish this. Im guessing for even it would be something like if(number % 2!=0)? What about for odd?
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Sep 26, 2014
I wrote a template function which use dynamic array as parameter. But if parameter is a empty array, it have compile error.
code:
#include <iostream>
int arry[] = {1,2,3};
int empty_arry[] = {};
[Code]....
compile error:
[zengchao@cmcc-server2 ]$g++ test.cpp
test.cpp: In function ‘int main(int, char**)’:
test.cpp:16: error: no matching function for call to ‘array_parameter(int [0])’
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Nov 30, 2013
I started making something for my class and the thing im getting stuck with is this function:
void ucitajOdgovore(string asocijacija[21]){
int brojac=0;
ifstream fajl;
string putanja;
/*srand(time(NULL)); int random=(rand() %5) +1;
switch(random){
[Code] ....
In the main, i pass real string array "asocijacije" in function which i use in it, and when i use it after this fun. i get an empty array. Its like it didnt happend and i cant see where i went wrong.
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Apr 7, 2014
program im creating that is a Mediastore. I have 3 forms one start form where you choose which form you wanna go to Lager or Kassa are the two choices. in these forms i have 1 listbox each that share the same Data. In my Listboxes i have objects of a class called produkts that consist of 3 variables Name,SerialNumber and Price. When i have added these objects to my listbox and they are showing i wanna be able to use my "go back" button to go back to my orginal form where i choose which form i wanna go to and then go to eather my Lager form or my Kassa form and the items are supposed to still there however that is not happening for some reason.
public Lager()
{
InitializeComponent();
}
[Code].....
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Aug 10, 2014
I am new to c++ and have started creating a dummy program to perform a simple task of writing a few strings to the console, which are first generated using random generation. When I execute the code, an extra line for each generated object appears in the console.
int gemNum;
cout << "This program calculates the value and type of gems
";
cout << "Please enter the number of gems: ";
cin >> gemNum;
vector<int> gemVector(gemNum);
vector<int> gemCollection = fillGemCollection(gemNum);
vector<int> gemSort = sortGems(gemCollection);
vector<string> gemResult = finalGemValue(gemNum, gemSort);
for(int i = 0; i<gemResult.size();i++){
string gemString = gemResult[i];
cout << gemString << endl;
}
This program calculates the value and type of gems..Please enter the number of gems: 4
10 hematite
40 carnelian
60 onyx
120 silver pearl
Press "e" and enter to end program
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Apr 10, 2014
I have tried to implement a much simplified version of boost::compressed_pair.What follows is a partially specialized EBO_pair<T1, T2> class template, written in C++11.The first type T1 is constrained to not be empty.The second type T2 may or may not be empty.
#pragma once
#include <memory>
#include <type_traits>
#include <utility>
namespace dsa
}
[code]...
Edit: added non-member swap() function template.
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Feb 9, 2013
I made two dimensional array to represent my (game) inventory. Slot is empty if its value is 0 and 1 if not.
Now i need to find if i can put new item in my inventory that can take up 4x2 slots. I tried this but it doesn't work as i expected:
#include <iostream>
int main() {
const int inventorySlotRows = 5;
const int inventorySlotColumns = 5;
int arr[inventorySlotRows][inventorySlotColumns] =
[Code] .....
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Apr 20, 2014
I'm having a problem filling a vector from a file. Basically, it is adding an empty element at the end. I'm new to Qt and haven't worked with file streams much so how to stop the stream before it adds the extra element.
void gui::get_data() {
mileage.clear();
QFile file(file_label->text() + ".txt");
QTextStream in(& file);
float m;
float g;
QString d;
[Code] ....
But, if I add another element to the vector and write that the file look like this.
//file after adding element
132654 0 02132014
132654 0 02132014
0 0
132998 22 02202014
I have it set to append at the moment so that is why the first line is repeated. I figure the problem is with if(in.atEnd()). I could fix it by deleting the last element right after adding it, but that seems like more of a hack than anything else.
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Jan 6, 2015
I am new in c programming. I want to write a function that will count the empty line of the file and display the content.
/* ***************************
** creator: firstprint *
******************************/
#include <stdio.h>
/* function that will identify if line is empty or not */
is_empty(char *buffer) {
while(isspace(*buffer)) buffer++;
if(*buffer==0x00) return 1;
[Code] ....
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Sep 13, 2012
Use your language’s native queue class to write the following program: create a class, Patient. The class has 2 members: name of type string; wait_time, a non-negative integer. Read definitions of patients from a file and add the patients to a queue. Write a loop that dequeues a patient from the queue and then decrement the patient’s wait_time. If the patient’s wait time is greater than 0, then the program enqueues the patient again. Otherwise it discards the patient. The loop continues until the queue is empty.
Header File
Code:
#include <string>
class Patient {
public:
Patient();
std::string name;
int wait_time;
bool empty() const;
[Code] ....
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Feb 23, 2015
I am developing 1 desktop application to my friend office,in that application i can store multiple images and i can retrieve the information for the same..My issue here is after retrieving the information when i click on update button I'm getting runtime exception i.e (Empty path is not legal exception)..
Here is the code which I wrote under updatebutton method:
public partial class CustomerDetails : Form
{
string imageloc = "";
string imageloc1 = "";
[Code].....
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Aug 25, 2013
I am creating a pizza program for ordering a pizza and I have removed all the errors except for two. I have tried everything I can think of to fix this problem so it will compile, but to no avail. The only errors left are:
1>------ Rebuild All started: Project: Pizza Order App Midterm, Configuration: Debug Win32 ------
1> stdafx.cpp
1> Pizza Order Midterm.cpp
1> Pizza Order App Midterm.cpp
1>c:usersindia-n-jerrydocumentsvisual studio 2010projectspizza order app midtermpizza order app midtermpizza order app midterm.cpp(57): warning C4390: ';' : empty controlled statement found; is this the intent?
[Code] ....
The entire code is listed below seperated into 1 header and 2 cpp files.
// OrderPizzaApp.cpp : Defines the entry point for the console application.//
#include "stdafx.h"
#include "Pizza_Order.h"
#include <iostream>
#include <string>
using namespace std;
// prototypes
Pizza_Order createPizza_Order();
[Code] .....
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Sep 20, 2014
I am writing this program that is supposed to read a file, put the data into an array, alphabetize, count how many times each word appears and print to an output function. I posted before on how my program had an error when I ran it but I have fixed that. Now my outputArray file is empty. It gets created but there's nothing in it.
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
using namespace std;
//global to this file
[Code] .....
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Aug 19, 2013
How to declare functions in C++
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Mar 6, 2015
I remember that the syntax exists I just don't remember what it is.I want to write a conditional function () prior to main (). in that function I'm using a variable that isn't introduced until main (). How do I let C know that I will be int'ng this function prior to the point where it is going to be accessed so that it doesn't freak out? alternatively is it possible to int the variable in both main() and my conditional function so that it exists? I imagine this would cause an issue because I would essentially be int'ng it twice.
I've done the cursory google searches however I don't think I'm using the correct keywords to get the results I'm looking for. If necessary I would be more than happy to post the code it's just a simple 40 line homework assignment.
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