There is only one difference between a struct and a class: The default access for struct members is public whereas the default access for class members is private. C++ comes from C and in C there is only one way to group data members together: a struct. Therefore, C++ has only structs. A class is a term used in object technology ... |
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Really you should post some text explaining your problem as well as the code. However your problem is that you have declared your structure as private to the class but you are returning it from a public function. The code calling the function will not have access to the type because it is private to the class so this leads to ... |
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I have written a SplayTree class, what makes me wonder is when I compiled it, it has something errors: error:'SplayNode' has not been declared you can see the code below that the SplayNode has been declared in private, why? And how can i fix it? And I have tried another way that declared the SplayNode outside the SplayTree and it works ... |
Are you saying that ChassisID is a public member variable, like in a struct?? You may need t post the code that creates pRep_Active_SLis t[i] and the class/struct declaration of Rep_Active_SList. hi.. good morning... thanks for reply me, ya..ChassisID is a public member variable of the structure BSMChassisSlotList_t. The declaration of ChassisID is as follows typedef struct _BSMChassisSlotList_t_ { char ChassisID[BSM_CHASSIS_SIZE]; ... |
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P: n/a Jim Langston I use a game engine using MSVC++ .net 2003 and have no problems. Some users of DevC++ who use the same engine crash at times when a copy of this structure is the return variable. I don't have access to the code that is crashing, but the developer has been changing functions that return the structure to ... |
Hi A while back when I was doing assembly programming, if I was defining a memory overlay (a DSECT if it helps) , I could add in a line such as this MEMSPACE DS 0H defining a reference to a zero sized element in memory (this is my way of understanding it, proper assembly programmers probably have better ways of describing ... |
There is a lot of info on this topic on google. But in Bjarne Stroustrup 's book page 225 he writes: "The declaration of Date in the previous subsection (declared as a struct) provides a set of functions for manipulating a Date. However, it does not specify that those functions should be the only ones to depend directly on Date s ... |
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Given the limited amount of information you have posted, I would say that you are defining the body of OpAmpDb::OpAmpDb() in the header file. I could be wrong though. But in the off chance I am correct, but the function definition in a source file. If I am wrong, it may help if you post the error messages being emitted from ... |
P: n/a Christopher Pisz This is a solution I thought about to some of the problems I had talked about in the "zero memory" above in the ng. While this isn't a MS specific post, let me walk you though the problem that MS created that I am trying to overcome They have functions: HANDLE CreateIoCompletionPort( HANDLE FileHandle, HANDLE ExistingCompletionPort, ULONG_PTR ... |
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As a general rule (and I'm sure I'll be corrected, because I believe you can do other things), a structure is used to store items of data, a method/function is used to do things..... so a structure might be able to STORE x and x^2, but a method would take x and CALCULATE x^2 Hope that makes some sense.... |
Hi there;-) I have the following struct: struct foo { union { unsigned __int64 ui64; char[8] c; }; }; what i now want to make possible is... foo a; foo b; int c; foo d; a = "abcdefg"; b = 12; d = (foo) c; so i think i need to globally overload the cast operator, isn't it? i know how ... |
I am trying to create a "pseudo-class" using structs. Member variables seem easy enough to do. However, trying to implement member functions has led to nothing but frustration. I have tried using function pointers, but when I do, I cannot figure out how to get access to the member variables. Here is what I have so far: typedef struct { int ... |
hi , i'm a C / C# programmer .. have'nt done C++, in C# .. . object instances of classes ( TextBox txt = new TextBox();) are reference types. Structs on the other hand are value types. In C++ i knw there are a few difference between classes and structs but i need to know if there are value or refrence ... |
subramanian wrote: What is the difference between a struct and a class ? > When should a struct be used and when should a class be used ? as already few friends told access difference in struct and class but i suggests you to write code related to struct in .c file and related to class in .cpp file, after that ... |
P: n/a aaragon Hi everyone. I'm trying to write a class with policy based design (Alexandrescu's Modern C++ Design). I'm not a programmer but an engineer so this is kind of hard for me. Through the use of policies, I want to customize the structure of a class. The idea is to investigate the use of several data structures. One option ... |
I am would love to be able to initialize a struct statically in my class, but the compiler seems to throw a fit when I do. I have something like // in h file class MyClass { private: static CK_INFO aStruct; }; // in .cpp file // yes, I know the strings must be blank padded MyClass::aStruct = {{1,0},"christian",0,"Whatever",{2,0}}; The struct ... |
I expect this has been covered somewhere, but I can't find it. Given: class A { public: A() {...does stuff...} }; struct S { A a; }; If I create an instance of S, is A's initializer guaranteed to run? Put differently, is the compiler committed to search down through many levels to find things with constructors? (I know it will, ... |
Hello, I'm learning C++ for a couple of days and play a bit with the algorithms provided in the STL. One thing I don't understand is the fact that classes inherited of functors have to be defined using structs. The code template struct Print : public unary_function { void operator()(type& x) { cout << x << endl; } }; ... |
vishnupriya.sureshbabu@gmail.com wrote:[color=blue] > What is the main reason for prefering class over struct? Access > specifires can also be used in struct. Is there any other reason for > using class other than inheritance? >[/color] None, there is absolutely no difference between a struct and a class. The fact that their default access specifier is different doesn't change that fact. Some ... |
Hi, What is the difference between having a struct with constructors and methods versus a class? In many C++ examples online I have seen code similar to this: struct Animal { Animal() { id = 0; name[0] = 0; } int id; char name[30]; }; Intuitively, I would understand structs with methods to be more data oriented (i.e. no virtual methods), ... |
Leif Gruenwoldt wrote:[color=blue] > Is it possible to safely cast a struct to a class? The contents of both > are the same size, however there is the issue of the class having > virtual functions which make the size of the class slightly larger.[/color] It is not safe to cast between unrelated types. If there is no conversion from one ... |
nurxb01@gmail.com Hi I have a very basic doubt. The application i'm working on has some old code already in place. There are some struct data type decleared in a .h file and are being used for RPC communication. Further in the application code at some places forward declearion for these datatypes are given as class . The code compiles without any ... |
P: n/a Bilgehan.Balban@gmail.com Hi, I am currently brushing up my c++ knowledge and I would like to ask you about the differences between classes and C structs, in the function/method perspective. 1) Is it correct to say that, a structure definition that includes function pointers only defines the function prototypes to be used with them, but not the actual implementations, whereas ... |
I am using Linux and Curses As I can remember - In Dos there is a possibility to write to a location of the screens memory. Maybe i could use fwrite to a fixed position of stdout.? What I want to do is to write formatted output (a long stringarray) which containing some line feeds). Is there some way to put ... |
This is a performance issue: Struct vs. Class. This is a performance issue: Struct vs. Class. I'm at that point in development where I need to make the app more stable. The program is a truck control and monitor system. Right now the app can have any number of trucks, let's say 5. Each has an engine, the shape of the ... |
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I am just learning C# and in the book "Presenting C#" by Christoph Wille it says "the difference between struct and class in C# is that struct is a value type and class is a reference type". It goes on to say that a struct in C# is "more suitable for scenarios in which you need a large number of small ... |
In C++, struct and class are synonyms. The only difference is the default access specifier of the members. I can never decide when to type "struct" or when to type "class". The line always seemed so fuzzy to me. I've been at this for years, but when it comes to struct vs class, consistency in my coding style suffers because I ... |
Because of some really good advice that jasonvene gave me on another post at: http://forums.devshed.com/showthread.php?t=188982&page=1&pp=15 I figured I asked before doing what I'm thinking of doing since it sounds like I'm going against what I was taught in the post above. I'm designing the graphics kit using DirectX (2d). I'm trying to make the maintenance of graphics be as easy as ... |
hello: i am attempting to put together a code that for c++. here is my problem, i can figure out the struct code, but the class is a problem. i am not clear on public(classes). i clear on private. this is the code i have so far. i just don't what to code when it comes to public. pls help!!! class ... |
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Sorry to be a nag, but does anybody have any thoughts about that code up there? I still can't figure it out. This is the last and only bump, I promise! o:) PS: Too bad there's not an angel smilie. There's even room for 1 more smilie in the corner of the smilie palette. |
with classes you have the ability to overload operators and protect the integrity of your data with private members. classes also *supposedly* make reuse of code easier, but i think well designed structures and functions do the same, just read Stevens for proof of that. so it's really what your more comfortable with, or rather what suits the task better. like ... |
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That was what I wasn't sure of (i. e. constructors being no-ops). Is that true of destructors as well? If so you may be right. I've planned to provide allocators with initializers though, in which case I still have to treat the initialization differently. Since the only common case for POD types would be 0-initialization though, I may be able to ... |
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