struct

LNK 2001 error with struct

Hello, I have a h- and a cpp-file with some calculations used in many of my projects. Now I tried to put them in a separate dll, so the files should not be included in every project. When linking I get a LNK2001 (unresolved symbol) error for a struct, however lib and dll are in the right place. I use the #ifdef TOOLS_EXPORTS #defin...

Struct containing pointers to itself

I am writing a LinkedList in C, the below code represent my Node definition. typedef struct { int value; struct Node* next; struct Node* prev; } Node; I understand (or think that I do) that struct Node not the same as typedef struct Node. Granted my code compiles and runs as it's supposed to, however, I get a lot of warnin...

Pointer not initializing with a struct as a parameter. Access violation writing location 0x00000010.

The struct looks like this: template <class Node_entry> Node<Node_entry>::Node(Node_entry item, Node *add_on) { entry = item; next = add_on; } And the *new_rear pointer does not get initialized, but &item is filled with user input. Error_code Extended_queue::append(const Queue_entry &item) { Node<Queue_entry> *new_...

Casting one C structure into another

I have two identical (but differently named) C structures: typedef struct { double x; double y; double z; } CMAcceleration; typedef struct { double x; double y; double z; } Vector3d; Now I want to assign a CMAcceleration variable to a Vector3d variable (copying the whole struct). How can I do this? ...

Array and struct initialize in C++

I would like to initilize some elements of an struct and array in C++. In C you can do: unsigned char array[30] = {[1] = 4, [20] = 4}; struct mystruct { int i; int j; } struct mystruct e = {.j = 2}; But I cannot do it in C++. Is there any way to implement this kind of designated initializers? ...

bool from a struct lead to "error: expression must have class type"

I have a struct defined as struct sData{ idx * id; int * stime; bool * result; unsigned int N; }; Then the code that uses it in numeric compute(numeric e, sData swabs){ numeric cache=0.0; int sid=0; while(sid<swabs.N){ if(swab.result[sid]) cache += log(e); else cache += log(1.0-e); sid += 1; } retu...

What's the major difference between "union" and "struct" in C.?

Possible Duplicate: Difference between a Structure and a Union in C I could understand what a struct means. But, i am bit confused with the difference between union and struct. Union is like a share of memory. What exactly it means.? ...

Differences between address-of and ref operators

In my code I'm passing around some structures by reference, declaring them mutable and using the & symbol. The problem is that in some place the fields are corrupted (happens only in release mode) and I don't know absolutely why. I have found a fix, using ref keyword instead of the address-of operator. I understand that you can intercha...

Objective-c access struct variable from an array of structs

I have a struct called Point typedef struct { GLfloat x; GLfloat y; } Point; create an array of Points: Point *sPoints; for(int i=0 ... // define sPoints somewhere else, I want to alter variables on those points. Why does this work: sPoints[100].x+=10; but this doesn't: Point pt = sPoints[100]; pt.x +=10; is there any way...

Question regarding memory allocation of variables in a structure (In C).

Possible Duplicate: Why isn't sizeof for a struct equal to the sum of sizeof of each member? #include <stdio.h> int main(){ struct word1{ char a; int b; char c; }; struct word2{ char a; char b; int c; }; printf("%d\t%d\n", sizeof(int), sizeof(char)); //Output : 4 1 printf("%d\t%d\n", sizeof(struct word1), sizeof(st...

Parameters for Structs in Scheme

I have this struct for people: (define-struct person ( first ; a string: first name last ; a string: last name sex ; a symbol: 'male, 'female eyes ; a symbol: 'blue, 'brown', 'green hair ; a symbol: 'blonde, 'brown, 'black, 'red mother ; a person: empty if not known f...

C: setting an array member of a struct through a pointer

I have a struct with an array as a member, and am trying to set that array using arrow syntax. What I have: typedef float Foo[3]; typedef struct { Foo foo; } Bar; Bar* f() { Bar* bar = malloc(sizeof(Bar)); bar->foo = {1.0, 1.0, 1.0}; return bar; } gcc says: error: expected expression before '{' token on the line bar->foo ...

Should I use a structure instead of a class to hold string only data in C#?

C# question. Say I have a customers class that has a bunch of props for storing string only data such as name postal data and phone numbers. I don't use this entity for ORM as I'm only adding it to some type of collection for use during app life cycle. Additionally I don't need to add any entity specific methods to it or persist the da...

qsort not sorting structure correctly.

Hi, I'm trying to sort a structure I've created via qSort however it seems to be be doing what I expect it to. This is my compare function int compare(const void *a, const void *b) { const INPUT *p1 = a; const INPUT *p2 = b; return ((p1->startTime) - (p2->startTime)); } Where INPUT is my structure and startTime is an int...

C++ initialize anonymous struct

I'm still earning my C++ wings; My question is if I have a struct like so: struct Height { int feet; int inches; }; And I then have some lines like so: Height h = {5, 7}; Person p("John Doe", 42, "Blonde", "Blue", h); I like the initialization of structs via curly braces, but I'd prefer the above be on one line, in an anony...

How to treat a struct with two unsigned shorts as if it were an unsigned int? (in C)

I created a structure to represent a fixed-point positive number. I want the numbers in both sides of the decimal point to consist 2 bytes. typedef struct Fixed_t { unsigned short floor; //left side of the decimal point unsigned short fraction; //right side of the decimal point } Fixed; Now I want to add two fixed point number...

C# initializing struct w/incomplete parameters + formula

Im sure this is simple but I've looked at it too long and I need an answer soon. I am new to C#. If I put GetCommission() within the struct I get error CS0188: The 'this' object cannot be used before all of its fields are assigned to outside the struct error CS0038: Cannot access a non-static member of outer type 'Ex5._3.Co...

help with pointers and structs and arrays in c

help needed printing array of pointers to structs where am i going wrong ? please help include <stdio.h> include <stdlib.h> define HOW_MANY 7 char *names[HOW_MANY]= {"Simon", "Suzie", "Alfred", "Chip", "John", "Tim", "Harriet"}; int ages[HOW_MANY]= {22, 24, 106, 6, 18, 32, 24}; struct person { char *name; int age; }; ...

Check if field exists in Matlab struct without loading it

I have a large struct in a .mat file. I want to check if a specific field is present in the struct without loading the .mat file. The .mat files are very large and I want to minimize memory use. Can I do this or must I use the I load it like this? Suppose the .mat file is called "test.mat" with struct s in it: load('test.mat') tf = i...

use parameter when populating a struct with dataset c#?

Hi! I have a struct in a web service in c#. When I use "Selet * from TABLE1"; in a WebMethod I get a fully populated struct. But when I add a WHERE clause, I get null in response. Why is this? I have searched everywhere for a simple explanation but haven't found one. How can I use a SELECT * FROM TABLE1 WHERE _id=" + id "'"; If I only ...