C/C++ :: Accessing Pointer Inside A Nested Structure

Mar 19, 2014

i had a structure as follows:
struct a{
 int x;
 struct b{
  int y;
  b *next;
 }b;
};

when i try to access as follows:
struct a *a;
a->b=a->b->next;

i got the following error: base operand of ‘->’ has non-pointer type

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C++ :: Accessing Inside Structure Via Struct Pointer To Struct Pointer

Jun 5, 2012

"
#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.

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C++ :: Accessing Classes Member Variables Nested Inside Another Class

Feb 22, 2013

I have two classes, a Package class and a Person class. The Package class has two Person objects has member variables, a Sender and a Receiver. While overloading the << operator for the Package class so that it will make an output label from everything in the Package class. Here is my code...

class Package{
public:
Person Sender;
Person Reciever;
int weight;
double cost;
friend ostream &operator<<(ostream &out, Package &pack);

[Code] .....

So my problem is on that last output line, I am unable to call Sender.getName()... etc. Is there a proper syntax so that I can access the members of the Person class while overloading the << operator for the Package class?

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C :: How To Access Nested Structure Using Pointer

Jan 22, 2015

I need to know how to access the nested structure using pointer, i mean i know how to do that when i have simple structure, for example:

Code:
struct person{
char fname[16], lname[16];
int age;
}

for this example i can use

Code: (*pointer).age
or
Code: pointer->age

But if i have structure like this:

Code:
struct date{
int day, month, year;
}
struct person{
char fname[16], lname[16];
struct date birthDate;
}

Then how can i access the birthDate using pointer?

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C :: Calling Function Via Function Pointer Inside Structure Pointer

Mar 14, 2013

I'm trying to call a function via a function pointer, and this function pointer is inside a structure. The structure is being referenced via a structure pointer.

Code:

position = hash->(*funcHash)(idNmbr);

The function will return an int, which is what position is a type of. When I compile this code,

I get the error: error: expected identifier before ( token.

Is my syntax wrong? I'm not sure what would be throwing this error.

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C++ :: Accessing Nested Elements Of Vector

May 1, 2015

so lets assume i have a nested vector in a set or vice versa o in a more general form a container in a container example...

Code:
std::set<vector<int> > my_tuple;

How do i access individual elements of lets say the first vector in the set! Or the last element in the 3rd vector?

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C/C++ :: Not Able To Initialize Structure Variable Inside Main Whose Structure Defined GL

Aug 27, 2013

I am trying to run a programme implementing a function with structures in c... which is:

#include<stdio.h>
#include<conio.h>
struct store  {
        char name[20];
        float price;    
        int quantity;

[Code] .....

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C/C++ :: Value Assignment To Structure Member Inside The Structure?

Oct 7, 2014

Is it possible to assign a value to structure member inside the structure.like.....

struct control{  
char tbi:2 =0;
char res:1 =0;
};

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C++ :: Accessing Private Members From Inside Class

Jan 10, 2013

Let's say I have the following class:

class MyClass {
private:
int m_myInt;
public:
int myInt() {return this->m_myInt;};
int myFunc();
};

Which of the following is to prefer;

int MyClass::myFunc() {
return 2*this->m_myInt;
}
or
int MyClass::myFunc() {
return 2*this->myInt();
}

The second one seems better? Are both OK? What's the best practice?

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C++ :: Vector In Nested Structure

Nov 26, 2013

I have a nested record structure in C++ that contains a FileHeader record, a RecordHeader record and a DataRecord record. The last item is an array of unknown size (at compile time). I have to open a file and read the array size and then create the array.

I have worked on this for some time and can't figure out how to make it work. I know the sample data I am using has 85 records. I insert 85 into the array size and it works fine. But how do I create a dynamic array or define a vector within a nested structure?

1. What is the best (easiest) method to accomplish this (array or vector)?
2. How would it be implemented/how do you add data to it?

PreviousLogRecord.FaultRecord.push_back(field1); // does not work
PreviousLogRecord.FaultRecord[recordNumber].field1 = somedata; // works with 85 in array size.
struct LogFileHeaderRecordType {
QString field1;
int field2;

[Code] .....

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C++ :: Passing Nested Structure Array To Function

Feb 27, 2014

I've been able to write the program completing all requirements except for one... creating a function that accepts a nested structure array. Here's the program:

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
struct PayInfo {
double hours; // Hours worked
double payRate; // Hourly payRate

[Code]...

I don't even know where to begin. Specifically, concerning all the aspects of the function.

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C/C++ :: Getting Segmentation Fault While Initializing Nested Structure Variable

Nov 13, 2014

I am not able to assign value into struct addrinfo variable through struct sort_result structure variable.

struct addrinfo {
   int ai_flags; /* Input flags. */  
   int ai_family; /* Protocol family for socket. */  
   int ai_socktype; /* Socket type. */  
   int ai_protocol; /* Protocol for socket. */  

[Code] ....

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C++ :: Undefined Reference Error When Accessing Static Variable Inside Member Function

Feb 10, 2013

I am modifying a set of static variables inside of the class's member function. The static variables are private. An example of what I'm doing is as below,

utilities.h
-----------
class utilities {
private:
static int num_nodes;

public:
void parse_details(char* );

[Code] ....

I get a compilation error in the function void utilities::parse_details(char* filename)

which says: undefined reference to `utilities::num_nodes'

compiler: g++

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C++ :: How To Use Structure Pointer Through A Structure Public Member Definition

Dec 7, 2014

Why doesn't this compile?

struct hi(){
void other();
}histructure;

void hi::other(){
std::cout << "Hi!" << std::endl;

[Code] ....

Makes no sense the structure is written before the structure member function is called so why is there compile errors ??...

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C :: Uninitialized Variables Inside A Structure

Aug 7, 2013

Let me say I have a structure

Code:
struct time{
char hours;
char minutes;
char seconds;
char dummy;
};

I have kept dummy as the data to be aligned.I will update hours, minutes, and seconds , but will not use dummy in any case. If I don't initialize 'dummy' does it make any errors ? Do I need to initialize hours, minutes, seconds as well before I use the structure ? If so is there any particular reason ?

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C :: Set Struct Member Variable For Structure Inside Def

Mar 12, 2014

This is with Linux gcc

Code:
typedef struct _a
{
int id;
} a;
typedef struct _b
{
a my_a;
my_a.id = 1; // error: expected specifier-qualifier-list before "my_a"
} b;

I get error: expected specifier-qualifier-list before "my_a"

I must set the id for the kind of struct created inside the struct def because main() will be casting based on this id. Thats how I will know which structure b contains by it's id, there could be hundards of different structs with different values I will cast to the correct one and know it's members by it's id. How do I ?

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C++ :: How To Define Enumeration Inside A Structure And Use It In Other File

Mar 5, 2014

I want to define enumeration inside a structure and use it in some other file

for eg

header.h
typedef struct dummy {
typedef enum {
ZERO,
ONE,
MAX
} NUMBERS;
// some member variables
} DUMMY; // end of the structure

otherfile.cpp

in this file i want to access both enumerations(for eg) ONE as well as the type NUMBERS.

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C/C++ :: Not Displaying Values Inside Structure Array (GCC)?

Apr 22, 2014

#include <stdio.h>
#include <string.h>
#define MAX 22
struct inven {
int Iid;
double uprice;
int uoh;
char name[MAX];

[code].....

doesn't seem to want to display the disp* fucntions at all

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C++ :: Malloc For Union Inside Structure Fails

Dec 27, 2012

I have some problem while allocating memory to a union inside structure. Below is the code i am using

ON SYSTEM1:

This works fine

ON SYSTEM2:

compiler complains saying "need structure or union type" while allocating MYSTRUCT1.

If I change:

shreyas[0].UnionAttr.struct1 = (MYSTRUCT1 *) malloc (sizeof(MYSTRUCT1)
to
shreyas[0].UnionAttr->struct1 = (MYSTRUCT1 *) malloc (sizeof(MYSTRUCT1)

This compiler on SYSTEM2 is happy. but second way does not look correct to me and compiler on system 1 complains about it. Which is the correct way to allocate memory?

If first one is correct then what should i look in for to avoid this error? Could this be an issue with compiler on SYSTEM2? If i use second method on SYSTEM2 code segfaults during malloc.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef struct mystruct1 {
int a;
int b;

[Code] ....

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C++ :: Composition And Member Access Inside Composed Structure

Jan 18, 2013

I have a question regarding composition and accessing members "deep" inside the composed structure. For example;

class A {
private:
int m_myInt;
public:
int myInt() const {return this->m_myInt;};
void myInt(int newInt) {this->m_myInt = newInt;};

[Code] ....

Now, from somwhere I have access to an object of type B where I want to update the A::m_myInt. How would you do this without "breaking" the whole purpose of private/public members?

B myB;
myB.m_a.myInt(3); // Not allowed, and not desireable

I thought about implementing access through functons kind of like;

A & B::a() {return this->m_a;};
myB.a().myInt(3);

but I'm worried that this exposes my B::m_a-object too much. This would allow

myB.a() = A();
, right?

The following is a more desireable way of acces, but doesn't work for updating;

A const & B::a() {return this->m_a;};
myB.a().myInt(3); //Disallowed? myInt(int) is non-const.

What about this? Is this a good way of doing it?

class A {
private:
int m_myInt;
public:
int myInt() const {return this->m_myInt;};

[Code] ....

I guess it works? It would lead to a lot of data shuffling in case of larger sub-components.I would really like to do the following without exposing my components so much:

B myB;
myB.a().myInt(3);

Can it be done?

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C++ :: Accessing Vector Objects Via A Pointer?

May 9, 2013

I have a pointer to a vector of objects, each object has an array and a couple of strings. how to access the data in the objects via the pointer.

Best tree::chooseSplit(vector <pgm> *ptr)
{
Best splits;
cout<<ptr[1].filePath; //not working!!!
}

filepath is a string in the pgm object. i also need to be able to access elements in an array that also exists in pgm.

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C++ :: Pointer To Array - Accessing Elements?

Mar 31, 2013

Code:
int arr[10];
int* p = arr;
int (*p2)[10] = &arr;

So, pointer p is a pointer to an array, I can use it to access elements of arr as in *(p+5).

Pointer p2 is a pointer to an array of ten integers. What is it for, how can I use it to access elements of arr?

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C++ :: Accessing Non-static Members Inside Static Member Functions

Sep 11, 2013

What are the workarounds for accessing the non-static member variables of some class(Say A) inside static member functions of another class(Say B)? I am coding in c++. Class A is derived with public properties of class B. Any pointers?

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C :: Accessing Values Stored By A Pointer Into Array

Mar 7, 2013

I am writing a C program to access a string into an array from a pointer array in Visual Studio 2010. Program is given below:-

Code:

#include <stdio.h>
#include <string.h>
void main() {
char data_a[6],data_b[6]="ABcde",*ptr;
ptr=&data_b[0];
data_a[0]=*ptr;
printf("%s",a);
}

I am getting some junk character first and then my actual data on console window. I want to where I am getting wrong and how to resolve it.

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C++ :: Why Can Initialize Array Nested In Structure Like Array

Feb 7, 2015

Example :
Code:
struct x {
int v[4];
};
const x test = { 0, 1, 2, 3 };

Why can I do this? How does the compiler know to write to this in the proper way? I get that v would be contiguous. Does that have something to do with it?

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C :: Pointer To A Char Inside Array

Jun 7, 2013

Alright, so I have a code that's not giving me errors, but it doesn't seem to retain what I put into an array. Not sure If I'm missing something...

Code:
#include <stdio.h>
int main (void)
{
const char *pointer;
const char alphabet[] = "ABCDEFG";

pointer = &alphabet[5];
printf("pointing to %c of the alphabet
", pointer);
return 0;
}

Trying to get my pointer to return the letter in the [5] spot or "F". Not receiving any errors when compiling, but I seem to get different answers every time I run it.

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