i have seen many c++ programs, where the private members from a header file are accessed in the source file. why is happening? As to my knowledge a private member cannot be accessed until it is friend function or member.
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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].....
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?
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 need to create a list of all members of a struct using the sturct definition as input. The struct is NOT part of the program, but is the input to the program.
The struct that I am using changes over time as features are added. I need the complete, fully qualified field names to then generate a table with all names with their offsets, type and length.
This information then allows me to create readers of the data that will run on different architectures, compilers and operating systems.
The struct currently has 800+ lines and uses typedef and embedded structs.
Perhaps this could be done creating LEX, YACC, Perl, SED, AWK or other language system.
I am currently doing the assignment about linked list. Here are some details information about what I am doing.. This program is C++ and should run on Visual Studio 2010. And it contains three file, two datastructure header and one main cpp file.
This program is trying to arrange and show some sports records. The main program which contain the functions such as reading the result text file(each result text file contain several records of athletes), removing a file, arranging the totalresult and printing it out. And the main program is already given and I cannot overwrite it.
But when I finished and try to build the solution and run it, I am not able to run the program and it give me somethings like these...
warning C4172: returning address of local variable or temporary
error C2248: 'Datastructure1::Datastructure1' : cannot access private member declared in class 'Datastructure1'
see declaration of 'Datastructure1::Datastructure1'
see declaration of 'Datastructure1'
This diagnostic occurred in the compiler generated function 'Result::Result(const Result &)'
And I have tried to comment each function part of the header file and see if can run or not. But I still fail to do so. Here are my codes...
#ifndef DATASTRUCTURE1_H
#define DATASTRUCTURE1_H
class Datastructure1 {
Public:
Datastructure1( );
[Code] ....
There are two header files and look quite long. They are all some linked list functions . I have read and learn linked list data structure before I complete this programs. However, when I complete the functions required, the function cannot be compile....
i have this vector:
#ifndef new_thing_Inventory_h
#define new_thing_Inventory_h
#include <vector>
#include <string>
using namespace std;
class Inventory {
[code]....
so i know i need to use .push_back or .pop_back, but the program im using dosn't even recognize that inventory is a created vector.
The reason that class members are private by default is because, in general, an object of a class should be a self-contained entity such that the data that make the object what it is should be encapsulated and only changed under controlled circumstances. Public data members should be very much the exception. As you’ll see a little later in the chapter, though, it’s also possible to place other restrictions on the accessibility of members of a class.
View 17 Replies View RelatedHow does an object access its private data members in copy constructor.
The relevant part of the code: Code: C::C(const C &obj)
{
x = obj.x;
y = obj.y;
}
Normally the object1 called "obj" cannot access its private data members outside. But in this situation it can access. How can it be explained?
Here are the complete code:
Code:
#include <iostream>
using namespace std;
class C{
public:
C(int,int);
C(const C &);
[Code] .....
How do i access the private array? I tried this and it's not working. Want i want to do is create class object in main and pass the string to constructor, and set m_make, m_model to that string. Then call the member function to output that.
const int BUFLEN = 256;
// class declaration
class CVehicle
{
[Code].....
I am trying to access the private member from main . The code is as follow. I wanted to call below function from main.
uint16_t Modbus::calcCRC(uint8_t u8length)
#define MAX_BUFFER 64
typedef struct {
[Code]....
I need to translate a C program to C by making variables in structures private(no classes yet!) and putting public inline functions. There's a good chance that I have much more problems with my code than I'm asking right now, but I have 4 spots that I'm currently stuck in and can't access properly.
My structures:
Code: struct Container
{
private:
int count;
char** lines;
int nlines;
[Code] .....
Basically, 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.
how to access the private and protected member functions of the class.....
View 5 Replies View RelatedMy 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].....
How would I change the private variables in the header files and the code in the cpp files for the primary indexes so they use a dynamic array or vector instead. For the primary index, the initial vector size will be 8.
header
#ifndef MY_PRIMARY_INDEX_H
#define MY_PRIMARY_INDEX_H
#include
#include
#include
#include
class PrimaryIndex
[Code] ....
Just wandering, will something like this work? header
Code:
#define func(arg) func_(arg) ...
static void func_(arg); code Code: #include "header"
int main()
{
func(arg);
}
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?
View 7 Replies View RelatedHow to access the name and file name members on line 42 and 43?
Code:
typedef struct {
char * name;
char * filename;
} FILES;
FILES * files[256];
}
[code]...
How to access the name and filename from within function?
*files[count].name = chTmp;
I am trying to use arithmetic on structure members read from separate text files into separate functions. I'm trying to do the math in the main function after calling the other two functions. I'm trying to divide nato_attack by pact_defence.
The warning I'm getting is: both are being used uninitialized in this function.
The goal is to read/write the info in the text files and to use them as any other variable, i.e. add, subtract, etc. in other locations in my code, i.e. functions, modules.
I "borrowed" most of this code from a youtube lesson and modified it for my needs.
Below is the contents of the two text files and my code.
This is for NATO
6
12 4th_mech_div mech div 14 16 7
12 5th_mech_div mech div 10 8 7
12 3rd_mech_div mech div 5 6 6
12 1st_mech_div mech div 4 6 7
12 2nd_mech_div mech div 12 14 7
12 6th_mech_div mech div 8 12 6
This is for Pact
3
10 1st_Guards armor div 12 8 6
10 2nd_Guards armor div 12 9 6
10 3rd_Guards mechanized div 10 9 6
Code:
#include <stdio.h>
#include <stdlib.h>
typedef struct {
char *unit_id;
char *unit_type;
char *unit_size;
[Code] ....
I'm trying to put file data into members of a class. Remember to type in the file name you want to open. Cool feature right? I just had Dbase.txt so I chose that.
Fixed stuff in the .txt. Now I need to figure out why it only does 1 set and then ends.
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <fstream>
using namespace std;
class INFO {
[Code] .....
Dbase.txt:
Bob
Guy
Programmer
M
9999.99
40
------------------
Little
Guy
Little Brother
M
0.0
3
------------------
The program is supposed to read a formatted .txt file and store the data into their respective [Class] Members. It will then output the data collected onto screen.I overloaded ifstream and istream. When I call for file>>ptr[i] to read the data, something goes wrong. It prompts me to input data (which is in istream overload).The Data in .txt file is as follows;
#ifndef STUDENTTESTSCORES_H
#define STUDENTTESTSCORES_H
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
[code]....
Below is my sample code of a C program. I am doing lot of processing, but my issue is I am getting a segmentation fault error in my main when I am putting the file names at the command line and using them. The program works great in Windows, but its giving error in Unix.
Below is the code of my Main function.
Code:
int main(int argc, char *argv[])
{
FILE *user, *requests;
char c;
user = fopen(argv[1], "r");
requests = fopen(argv[2], "r");
//For users
struct userStorage *USHead = NULL;
//struct users *userHead = NULL;
[Code]...
I have written my program and it works when I keep everything in the header files, and then have my main. I am now splitting them up into implementation files, but Eclipse keeps giving me errors. It gives me error at every opening brace of the constructor and functions. It says on all of them "Redefinition of (name of constructor or method), Previously declared here." What am I doing wrong, because it works in the header file?
#include "KeyValuePair.h"
template<typename Key,typename Value>
KeyValuePair<Key,Value>::KeyValuePair()
[Code] .....
I am working on an assignment in which i have to perform th following task
myClass itsObject1,itsObject2;
itsObject2=5000+itsObject1;
I have defined overloaded operator as follows in the header file but in the cpp file of the class it gives error.
friend vli &vli::operator + (int &a,vli &obj);
How to define it in cpp file of my class?
What is the right syntax for implementing the .cpp of a template class?
Consider this LinkedList.h file:
Code: #include<iostream>
#include"Iterator.h"
template <class T>
class LinkedList {
[Code] ....
How should the implementation for the LinkedList constructor, for example, should look like in the LinkedList.cpp file?
I tried this:
Code: #include "LinkedList.h"
template <class T>
LinkedList<T>::LinkedList<T>() {
// constructor
}
LinkedList<T>::~LinkedList<T>() {
// destructor
}
But the compiler wouldn't accept it.
