I have a queue of structs. I would like to access one of the two pieces of data at the front of the queue that each struct maintains.
Here is some of my code:
#include <iostream>
#include <cmath>
#include <cstdlib>
#include <iomanip>
#include <queue>
using namespace std;
[Code] ....
What I am asking is how do I get the priority of the struct item at the front (lane1.front()), in this case?
I am parsing a binary data file by casting a buffer to a struct. It seems to work really well apart from this one double which is always being accessed two bytes off, despite being in the correct place.
Code:
typedef struct InvoiceRow {
uint INVOICE_NUMBER;
...
double GROSS;
...
char VAT_NUMBER[31];
} InvoiceRow;
If I attempt to print GROSS using printf("%f", row->GROSS) I get 0.0000. However, if I change the type of GROSS to char[8] and then use the following code, I am presented with the correct number...
Code:
typedef struct example {
double d;
}
example;
example *blah = (example*)row->GROSS;
printf("%f", blah->d);
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] .....
"
#include <stdio.h>
struct datastructure {
char character;
};
void function(struct datastructure** ptr);
[Code] ....
These codes give these errors:
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
These errors are related to
"
*ptr->character='a';
printf("Ptr: %c",*ptr->character);
"
I want to access "character" data inside the structure "trial" by a pointer to pointer "ptr" inside function "function",but I couldn't find a way to do this.
The program I'm working on is a very basic relational database. I've isolated my problem for simplicity. I get a segfault right here when I try to access db->relationCount. I tried printing db->relationCount from within loadDB and that worked,
[code]
loadDB(db, configFile);
printf("%d",db->relationCount);
fflush(stdout);
I've been working for some number of days on this code to take information about movies from both a file and the user, store the infos in an array of structs, and at the end, write all the info out to a file. I'm having some problems with an error message reading:
"prog.c:102:11: error: subscripted value is neither array nor pointer nor vector"
this error occurs in many lines (which I will label specifically below -- they are everywhere where I am trying to access/modify an individual element of a struct element of the array).
A few examples of where I am having the problems are lines:
39, 52-55, 70, 72, and 86 (and more of the same exact variety).
I am obviously rather systematically doing something wrong, but I am quite certain all of these are the exact same mistakes.
I pull up also 2 or 3 other errors, but I don't think they are related and should be able to fix them quickly once I work out this conundrum.
#include <string.h>
#include<stdlib.h>
#include <stdio.h>
int moviecount =0;
typedef struct{
int year;
[Code] .....
I've been reading the tutorials on Friendship and Inheritance [URL] ..... but I still don't understand why I can't access members of the same struct type.
bool wordBeginsAt (int pos) {
if (pos == 0)
return true;
///use the 'message' string
Message go;
return isAlphanumeric(go.messageText[pos]) && (!isAlphanumeric(go.messageText[pos-1]));
}
The code above is located in a source file, where the function isAlphanumeric passes a char value, and Message is the struct containing the string I want to access. Below is the declaration of the struct and string located in the corresponding header file.
struct Message{
.
.
.
private:
std::string messageText;
};
My frustration comes when I try to call and assign messageText like the tutorial does to its private members, but I keep getting an error saying I can't access the string because it is a private member. Is there a way to access the string without having to pass it through the function wordBeginsAt?
I have a vector (structures) in a struct (instances). I make a declaration of this struct called instance. The vector is a 3-layer vector of pointers, like so:
vector < vector < vector<scene::IAnimatedMeshSceneNode*> > > structures; (The type is from Irrlicht 3D). I have 3 nested "for" loops which looks similar to the following:
for (int a = 0; a < instance.structures.size(); a++) { /*note:vector size previously set*/
for (int b = 0; b < instance.structures[a].size(); b++){
for (int c = 0; c < instance.structures[a][b].size(); c++) {
if (1) { //checking value of variable not included in snippet
(instance.structures)[a][b][c] = smgr->addAnimatedMeshSceneNode(fl);
(instance.structures)[a][b][c]->setPosition(renderPos);
}
}
}
}
The problem is in these two lines, I think:
(instance.structures)[a][b][c] = smgr->addAnimatedMeshSceneNode(fl);
(instance.structures)[a][b][c]->setPosition(renderPos);
These are currently referencing the pointers, it seems. The program compiles but crashes at this point. I need them to reference the values of the pointers. Problem is, I don't know where to put the dereference operator (*). Where should it go?
I currently have a file which allows inputs to record different transistor types. I then have the task of accessing this structure, find a certain manufacturer ID, and print the information about this particular transistor.
My problem is accessing the array to search through.
Here is my code:
Code:
#include "stdio.h"
const int IDLEN=30; //All constant values defined
const int POLARITYLEN=3;
const int MAXSTOCKITEMS=10;
//First structure defined
struct TransistorRec {
[Code]......
The errors I am currently getting are on line 54 'expected primary-expression before "struct"' and on line 60 ' 'maunfacturersID' undeclared'
I'm currently working on the ioquake3 engine . The ioquake3 engine is separated into 2 different main threads at runtime: the gamecode and the engine. Both are communicating but not all information and my problem resides here.
In the gamecode, there's a struct called gentity_t which contains a lot of fields:
Code:
typedef struct gentity_s gentity_t;
struct gentity_s {
entityState_ts;// communicated by server to clients
entityShared_tr;// shared by both the server system and game
// DO NOT MODIFY ANYTHING ABOVE THIS, THE SERVER
// EXPECTS THE FIELDS IN THAT ORDER!
//================================
struct gclient_s*client;// NULL if not a client
[Code] ....
This whole entity is passed to the engine at runtime, but only the first two fields are declared for the engine:
Code:
// the server looks at a sharedEntity, which is the start of the game's gentity_t structure
typedef struct {
entityState_ts;// communicated by server to clients
entityShared_tr;// shared by both the server system and game
} sharedEntity_t;
My problem is that I need to access the health field of gentity_t from the engine. Technically, this is possible, but the health field is not declared in sharedEntity (which is the same memory address than gentity_t in the gamecode), so this is not straightforward.
I am looking for an elegant way to do this, and my constraint is that I must not edit the gamecode, only the engine.
The solutions I've thought:
- Just copy the whole gentity_t fields into sharedEntity_t. This would work I think but would be redundant, and I would like to avoid copying this huge set of fields.
- Include the two headers files declaring the gentity_t and sharedEntity_t structs, and create a Getter and a Setter functions that would cast a gentity_t over a sharedEntity_t and return/set a field. The problem is that I can't simply include them because they are both including some common headers files and this produce a recursive include error (and I can't modify the files to add a check, these are normally in the gamecode).
- Directly access the health field using a clever memory pointer, but I don't even know if that's possible given the huge number of fields prior health with many different types?
I was wondering what the best way was to access data outside the function it was created in. I have the user input a data in a custom namespace function, and now im trying to access all those data points in a different function.
View 9 Replies View RelatedBasically, I've got one object which has to access private data in another object... and can't.
Here's the specifics: I'm writing a little war game program where players deploy units (soldiers, tanks, planes, etc.) onto a gameboard. Players and Units are modeled as objects:
Code:
class GameUnit {
public:
string GetName() {return Name;}
protected:
string Name;
};
class Player {
[Code] ....
Here's the problem: In the above code, Player's ListUnits() function doesn't work because Player can't access GameUnit's GetName() function.
Specifically, here's the compiler's error message:
Code:
In file included from Main.cpp:18:
Player.h: In member function 'void Player::ListUnits()':
Player.h:47: error: 'GetName' undeclared (first use this function)
Player.h:47: error: (Each undeclared identifier is reported only once for each function it appears in.)
I've tested enough to realize that the problem is the GameUnit::GetName() function is a public function within the GameUnit object. Why can't a Player call this function? Making both friend classes of each other doesn't work.
I have a paradigm in a loop of queues of a vector,if a condition is true,increase sizes of the queue of that particular queue in the loop of queues, if condition is false, the queuesize is left as such in loop of queues. After this operation i need to search the queue sizes of all queues and enqueue in the shortest queue.
I want to do something like the code given below
#include <vector>
#include <queue>
int min_index = 0;
std::vector<std::queue<int> > q
std::size_t size = q.size();
[Code] ....
How to implement this logic?
will q[i].size=q[i].size+5 increase the queuesize by 5 for the ith queue?
I've got a Dev Express hierarchical grid and I need to which row is in focus in the level that's in focus. In the code below I need to replace "gridControl1.FocusedView.GetRow(0)" with "gridControl1.FocusedView.GetRow(x)" where x is the row number in the focused row but I can't find a property for it.
private void gridControl1_Click_1(object sender, EventArgs e)
{
//int i = gridView1.GetFocusedDataSourceRowIndex();
[Code]....
I have a header file that declares some fields as private, I then have a class that I need to compare two of the objects' information for equality but neither of them are the calling objects. I cannot alter the header file. How would I go about comparing private data fields? I will enter a brief bit of code for clarity.
Code: // Header File
// stuff.h
class stuff
{
private:
int* arr[20];
int size;
};
bool equal (const stuff& a, const stuff& b);
[code].....
My code is here [URL]
void Player::Display() const
{
cout << "
Player Name: " << GetName() <<
"
Grade: " << GetGrade() << "
G.P.A. " << GetGPA() << endl;
}
The problem occurs in here, I get access violations, is there a way to this while keeping Display const or is this code valid and my problem is somewhere else and not being caught in the debugger? I tried to make the return types const - but that didn't work .....
//Getters need const twice for this to work?
const char* Player::GetName() const {return m_name;}
const int Player::GetGrade() const {return m_grade;}
const double Player::GetGPA() const {return m_gpa;}
[Code].....
So this is the last part of a program I've been working on for four weeks now. This question may be a tough one considering the amount of files included in the program.
The program is to read in a file of requests between two cities, read in a file of flights and cities that occur between the cities. It then checks to see if there is a path between the flights and output an itinerary. I have the correct itinerary outputting, but when attempting to output the associated flight number and price according to the city, I am getting odd data. How can I output the correct flight number and price associated with each flight on the itinerary.
I'll post out the output I am currently getting and the section where I am outputting the data. I'm sure I'll need to post more files so the program can be understood.
Don't want the code done for me, just a point in the right direction! I don't want to let this program defeat me!
Output: Code: Request is to fly from Atlanta to San-Diego.The flight itinerary is:
Flight # From To Cost
10 Atlanta Chicago $134529069
10 Chicago Miami $134529069
10 Miami Dallas $134529069
10 Dallas San-Francisco $134529069
10 San-Francisco San-Diego $134529069
This function finds a path between cities. Code: bool flightMap::IsPath(string originCity, string destinationCity){
StackClass aStack, bStack;
flightStruct flightRec;
string topCity, nextCity;
bool success;
int index = 0;
[Code].....
I was looking at some linked list material and was wondering something. Can you initialize a data member inside a struct like in C++? i.e.
Code:
typedef struct node
{
int data;
struct node * next = NULL; // this is the line in question
} LLnode;
I am working on this project where I need to see if data in a struct has changed and if so I need to do something. With that being said, is there a way to check to see if data in a struct has changed. My first approach was to make a copy of the struct and compare the original struct with the copy but I was having problems with the operator==.
View 2 Replies View RelatedI was working with binary search tree and came up with the solution:
Code:
#include<stdio.h>
#include<stdlib.h>
typedef struct data {
int x;
struct data *left;
struct data *right;
[Code] .....
I have the following code and I am trying to do simple math calculations to the data. I need to take the car price (y) minus down payment (z) and then divide that quantity by 12 times "yearsx" That answer is then assigned to x. The problem is that x will not print the correctly!I also noticed that if I increase the "count" to amnything higher than the number on lines in the file, I get the correct value for x but only on the last set of the struct..my file reads as follows:
last_name first_name car_price down_payment years
johnson bill 10,000 2,000 3
When I printf the struct to the screen, i need to do the following:
x = (10,000 - 2,000)/(12*years);
but this is the math part that wont work. I have checked and doubled checked number types and I cant get it right.
Code:
#include<stdio.h>
#include<stdlib.h>
#define FILENAME "file.txt"
#define SIZE 100
}
[code]....
I have a struct like this:
Code:
struct String{
char* data;
std::size_t size;
};
I would like to be able to create const variables of this type for string literals.
Code:
const String message;
Is there an elegant way to create a const String like this when data is a string literal?
I tried this:
Code:
const char *string_data = "Hello";
size_t string_size = strlen(string_data) + 1;
const String string = {string_data, string_size};
The problem with that is that string.data isn't considered const during the initialization of the String struct so the compiler throws an error. It doesn't feel very elegant to do it like this either way.
Is there an elegant solution to this problem? I would like to avoid making a copy of the string literal.
How can I read this file in to my struct?
12345Joe Lim KH879.00
12233Kay Suet Yee35.98
23781Leong Jing Yang 10.00
67543Woon Tian Yi500.50
struct master {
unsigned short int IDnum;
[code]....
not working
at my work we use a static analysis tool and it is pointing out some uninitialized variables. One of which is a class member variable which is a C struct. Now, that variable is already declared in the header file for the class.
Currently in the class constructor I am doing:
Code:
memset( &thestruct, 0, sizeof( thestruct ) );
Is there a C++ way to do this? I Googled this but all I really found was:
Code:
StructDef thestruct = {};
Which doesn't really apply here.
#include <stdio.h>
#define MAX_USERS 20
struct {
char ID[10];
char Name[40];
int Pos;
[Code] .....
I was attempting something weired with address to move data around when I discovered that the size of the array is not what I expected. I am passing this structure as &Users to a function that declares it as a void *, then I can deal with chunks of data (memmove) and not have to worry about index or things like that. However...sizeof is returning something I do not understand.
Im having trouble creating a struct within a struct node. the program suppose to hold students firstname, lastname, and gpa in a node therefore creating my linked list. Line 26 keeps saying that cannot convert parameter 2 from 'studentType to std::string
#include <iostream>
#include <string>
using namespace std;
struct studentType{
string firstname;
string lastname;
double gpa;
[code].....
