C++ :: Fixing Circular Dependencies With Pointers
Dec 18, 2012
I've been making a project that requires different files to have access to objects declared in other files such that circular dependencies are created. I've done some research and discovered that pointers and forward declarations should be able to fix this.
Example:
File 1 declares variable x, must edit x and y
File 2 must edit x and y, declares variable y
I know this isn't the best example, as you could probably declare x and y in the same file, but please suffice it to say that I'm unable to do that in my project.
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Jan 29, 2014
I have a circular queue using DLL which is using globally declared pointers. The problem now is that it is not being initialize properly or being cleared thus my code is not working as expected.
In my code you will be asked how many nodes do you wish to enter "i made 2 default for now", after that you may then add or delete the node. add only works now since delete is still on progress.
When you add the nodes "2 nodes by default" the program will only record the latest input so if i were to input 1 and 2, only 2 will be displayed. I know that this maybe because of my *first and *last variables not being initialize properly.
How should i really work with global pointers? Also im really new to project file programming and not a fan of pointers or linked list at all.
main.c
Code:
void main(){
int ch, number, numdum = 0;
n *new, *ptr, *prev, *first, *last;
first = NULL;
last = NULL;
clrscr();
printf("Enter number of nodes: ");
scanf("%d", &number);
[Code] .....
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Feb 23, 2015
I have a list of calculated fields, these fields reference other fields in their calculations. I need to create these fields beforehand as they will not exist.
I was wondering what would be the best approach for this Example List
Field1 has Field2 in the calculation
Field2 has Field4 in the calculation
Field3 has Field1 in the calculation
Field4
I'm not sure on how to approach this.
Create list in this order
Field4
Field2
Field1
Field3
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Mar 4, 2013
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.)
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Mar 31, 2013
I want the 'counter' loop to go through twice, each time reading in 15 characters from the standard input, then going through the evalutor
Code:
#include <stdio.h>
#include <ctype.h>
int main (void)
{
char inputtedhand[64];
int NumC=0, NumD=0, NumS=0, NumH=0;
}
[code]...
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Dec 7, 2014
Design and implement the class myArray that solves the array index out of bound problem, and also allows the user to begin the array index starting at any integer, positive or negative. Every object of type myArray is an array of type int. During execution, when accessing an array component, if the index is out of bounds, the program must terminate with an appropriate error message. Consider the following statements:
myArray<int> list(5); // Line 1
myArray<int> myList(2,13); //Line 2
myArray<int> yourList(-5,9); // Line 3
The statement in Line 1 declares list to be an array of 5 components, the component type is int, and the componentst are : list[0], list[1]…list[4]; the statement in Line 2 declares mylist to be an array of 11 components, the component type is int, and the components are: mylist[2],…mylist[12].
This is what I have so far:
#ifndef H_myArray
#define H_myArray
#include <iostream>
using namespace std;
template <class myArray>
class myArray
{
public:
private:
return 0;
};
#endif
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Oct 21, 2014
Im writing program for a rail fence cipher that should run from the command prompt and take in two .txt files, one containing the key for how many rails there should be (between 1 and 25) and the other containing the message to be encrypted. Both of those txt files should be entered from the command prompt, taken in with the program's arguments, not asking the user for input I think I have the logistics of how to get the program to encrypt it worked out, but every time I try to run the program it keeps on crashing.
The program should run when I enter this:./railcipher samplekey.txt samplemessage.txt
I'm pretty sure my issue lies within my first few lines of code, with the main(), or with the FILE*, but I dont know what I would need to change it to for it to work properly.
Code:
#include<stdio.h>
#include<string.h>
#include <stdlib.h>
int main(int argc, char **argv[])
[Code]....
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Oct 15, 2014
If I have an array and all I have is an upper limit on how big the array can get, and if the number of elements that get added can be considerably smaller than this limit, is it always the right choice to declare a pointer and just reallocate extra memory whenever the array grows? For instance, instead of declaring int a[max] I can declare a pointer int *a and than just realloc when I add elements.
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Mar 6, 2015
So I have to write a step in my program that reads in up to 8 variables. Simple, but if the User submits an invalid value, I have to give an error message and ask him to re-enter the value until he enters a valid number. Here's my while loop that works perfectly:
Code:
while (true) {
printf("
Enter the mark given by Judge 1: ");
scanf("%f", &m1);
if ((m1 >= 0.0) && (m1 <= 10.0)) {
break;
}
[code]...
I'm not sure what to write in the else statement to make the programme understand that it has to repeat the exact same step but without adding 1 to index. Is this possible or do I have to suck it up and just use while loops instead? I'm very new to programming.
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Jan 29, 2013
I need to circular right shift a cstring in C++
Let's say I have unsigned char test[10] = "HELLO!!!"; How would I go about circularly shifting this to the right? Inline assembly instructions would be ok too
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Aug 30, 2013
Any algorithm or function to rotate a displayed circle. To turn it 360 degrees like a car-tire. (It's needed to turn a turn-table in a model-railrod control program) .....
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Mar 15, 2013
It's compiling but it's not working, it enters in stack overflow. It's a Doubly Linked List I'm compiling in Visual Studio. I think there's nothing wrong with this declaration, but there's just might be it:
class ListItem;
class List {
public:
ListItem *firstItemRef;
[Code] .....
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Jan 17, 2015
I need to create such a function that the content of the first is put into the second, the content of the second into the third and the content of the third into the first.
For example, output should be like this
3
2
1
But the code below prints out:
1
2
2
Where am I making a mistake?
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
[Code]....
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Jul 30, 2014
Is there a way to make a circular progress bar in WPF without using another library or NuGet Package?
Like a tutorial on how to make it from scratch?
Right now, I'm using the existing ProgressBar UserControl but it looks horrible especially after I change the Foreground color from Green to DarkBlue.
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Jan 23, 2014
I have ran into some sort of Circular dependency between two classes.
Forward declaration doesn't work as I'm allocating the memory for pointer array of Student and it requires the default constructor.
P.S I'm aware I haven't written the BIG 3, it's an incomplete code. Just want to know how to resolve this dependency.
class Student;
class Course {
char *name;
Student *s[3];
[Code].....
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Oct 6, 2013
I am stuck with how to make a circular queue that are based on a struct. Have been reading about the implementation but cant really understand it fully. Here is what i got so far.
Code:
#define SIZE 10
typedef struct {
char reg;
char brand;
int modelyear;
int mileage;
[Code] .....
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Nov 7, 2013
Today I faced a problem where I had circular dependency in my template arguments. I was trying to make a class hierarchy similar to:
template<class BType>
class A_base {
public:
BType* getB();
};
[Code] .....
Basically I had objects that were of type A<B<A<B<...
Basically I have a tree like structure of heterogeneous types that must facilitate two-way interactions where A's can call B's and B's can call A's. This structure is useful in many contexts the difference is the methods A and B provide are different in each of these contexts. Instead of adding the getA and getB and all the other connectivity methods in every version of A and every version of B, I wanted to create a base class that managed this automatically.
Another piece of advice was break up your code so there is a forward-only and backwards-only dependent types. This is not a complete solution because the two cannot know about the other and this does not really facilitate arbitrary two-way communication (where A calls B then B calls A back). It also makes the code more complicated in that I have two sets of objects and interfaces.
So the solution was to make the template arguments specific to the things I wanted to be flexible. The connectivity interface of A_base and B_base should be constant. Hence that cannot be in the template parameter. It was merely the traits that I wanted to make flexible so... I came up with this solution:
#include <iostream>
template<class aTraitType,class bTraitType>
class A;
template<class aTraitType,class bTraitType>
class B;
[Code] ....
Now this compiles and works great. The problem is that aObj and bObj cannot call their opposite within a trait method because print() does not know anything about the connectivity. So the solution there was to make traits an abstract base class. Then magically everything works!
#include <iostream>
template<class aTraitType,class bTraitType>
class A_base;
template<class aTraitType,class bTraitType>
class B_base;
[Code] .....
So this outputs the following. Clearly there is two-way communication!
Class A is not connected to B
Class B is not connected to A
Class A at 0x7fff25d1aa10 reporting for duty
Class B at 0x7fff25d1aa00 reporting for duty
Class B at 0x7fff25d1aa00 reporting for duty
Class A at 0x7fff25d1aa10 reporting for duty
Class A at 0x7fff25d1aa10 reporting for duty
Class B at 0x7fff25d1aa00 reporting for duty
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Jan 30, 2015
I've been making a circular linked list and I'm trying to assign each list a "name" and its next "link" but when I run my code it crashes.
Soldier *Head;
Head = NULL;
string names[] = {"Arman","Bogut","Castro","Damascus","Elene"};
for (int i = 0; i < 5; ++i) {
[Code] .....
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Apr 28, 2015
I have this program. I am trying to do this Circular List but i think something going wrong. The first of all is the list.The second is if my code for delete and select function are correct and the third i would like my program getting a "n" number of names and then make the circural list then print it and then when i select a number delete every node until give us the only one left.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 10
#define NUM_PER_LINE 6
typedef struct node {
char name[SIZE];
struct node * next;
[Code] .....
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Oct 31, 2014
I want to write a program where one core (core 0) will fill the FIFO and other core (core 1 ) will delete the data from FIFO.
Core 0:
I create a fifo
Code:
struct node
{
int info;
struct node *ptr;
}*front,*rear,*temp,*front1;
And my en-queue function is in core 0 and writing to specific memory location..(which works perfectly)
Code:
void enq(int data)
{
if (rear == NULL)
{
rear = (struct node *)malloc(1*sizeof(struct node));
rear->ptr = NULL;
rear->info = data;
front = rear;
[Code] ....
Now the problem is in the core 1. Here I am unable to read the values from the specific memory location. I am getting garbage value. Where I am doing some stupid error.. I did not understand
Code:
(front->ptr) = (unsigned int *) memory_location;
When I print the (front->ptr) it shows correct memory address but inside the De-queue function in core 1, I am getting wrong value..
Code:
int deq(int buf[n]) {
front1 = front;
printf("Val %d ", front->info); // showing wrong value
if (front1 == NULL) {
printf("
Error: Trying to display elements from empty queue");
return 0;
[Code] ...
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Jun 28, 2013
/* Implementation of a circular queue of Array containg names.. */
# include <stdio.h>
# include <conio.h>
# include <stdlib.h>
# include <string.h>
# define QSIZE 5
typedef struct{
[Code] ....
I changed my code. but whenever i typed in the ILoveBacolod it takes it as a whole, and if i deleted it deletes the string not the letter. for example:
Enter String: ILoveBacolod
Enter a command: Delete (D)
Output: LoveBacolod
Enter a command: Delete (D)
Output: oveBacolod
Enter a command: Add (A)
Enter a character: z
Output: oveBacolodz
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Feb 27, 2014
When I run this in main it gives me a windows error message. I believe it has something to do with my insertAtEnd function but I've gone over it a million times....
#include<iostream>
#include<string>
#include<vector>
#include"RhymeGame.h"
using namespace std;
Game::Game() {
head = NULL;
[Code] ....
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Dec 2, 2014
Should my if statement be
if (tail== NULL) or if(tail->next == tail) ?
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Apr 25, 2015
I print the original list, then reverse it, then try to print it again. Here is what I get when I do that:
So that second line should print 2 1 4 5
Here is the reverse function:
void reverseCirListDeque(struct cirListDeque *q)
{
struct DLink *curr = q->Sentinel;
do{
[Code].....
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Nov 30, 2014
Why is it sufficient to only have a pointer to the last node of the list?
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Jun 11, 2014
Each of my header includes is protected by directives. I think I don't have to include Boolean in my work space because it is already included in the external dependencies section. and the Boolean.h is in the include path.
MachineShop, Boolean etc got undeclared identifier error
Tried to comment out the directives, to no avail.
Code:
#include <iostream>
#include <string.h>
#ifndef BOOLEAN_H_
# include "Boolean.h"
#endif
#ifndef PROCESS_H_
# include "Process.h"
#endif
#ifndef MACHINESHOP_H_
[Code] ....
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