Is there way to find the size of structure pointer size? When we tried to get the size of structure pointer will get size of address(@ location) which would be 4 bytes long. But I want to get the size of all structure members size using structure pointer.
View 1 RepliesWhy 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 ??...
I have a doubt related Size of empty structure. I know the answer of empty structure is "0".
How and why the Result got ZERO..??
struct st
{
char a;
short b;
char c;
}
what will be size of structue.
Program to create client server interaction for store data into map using structure and pointer(without memory leak).
View 1 Replies View RelatedI'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.
"
#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.
const free_throws & clone(free_throws & ft) {
free_throws * pt;
*pt = ft; // Copy info
return *pt; // return reference to copy
}
This is a code snippet extracted from C++ Primer Plus book. However, it is really confusing. I don't really understand the free_throws * pt;
as far as I know, a pointer has to point to a memory address, and it is best to initialize it when it is declared. However, according to the code snippet above, the pt isn't initialized to any address. Isn't it dangerous when we declare a pointer without initializing it before we use it?
I thought it is supposed to be like this
free_throw * pt = new three_throw;
// or
free_throw * pt = & ft;
BTW, free_throw is a structure.
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?
I am trying to wright a program that takes student grade data from a command line file, calculates a final grade, and copies the final grades to an output file. So far I have two functions, one that creates a student structure by allocating memory for it and returning its address, and one that should take that address and fill it with data from a line from the input file. My ultimate goal is to use a linked list to connect all the structs, but for now I just want to get the functions working. When I run what I have so far, I get an error C2440 (using visual 2010) that says "cannot convert from 'cStudent *', to 'cStudent', and points to the line where I call my fill function. How should structure pointers be passed?
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student // Declaring student structure globally.
[Code] .....
Also, here is a sample of what a line from the input file would look like:
Bill Gates, 60, 54, 38, 62, 65, 60, 50
I have written this program
Code:
#include <stdio.h>
#include <string.h>
int main(void) {
struct point {
[Code] ....
error: request for member is not a structure or union
printf("%d
,%d
",p1->i,p1->j);
I was just trying to typecast a integer pointer to structure pointer, but throws error as shown.
#include<conio.h>
#include<alloc.h>
#include<string.h>
struct node
[Code]....
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
I am trying to create a callback system for input events in my game engine.
Here is a cut down version of the EventManager.h file
#include "Controls.h"
#include "Object.h"
enum MouseEventType{PRESSED, POINTER_AT_POSITION, PRESSED_AT_POSITION };
[Code].....
This works if the function pointer being passed to the event manager is not a member function.
I have two other classes Scene and Object that could potentially use this EventManager to create callback events. Scene and Object are both pure virtual objects. How can I pass a pointer to a member function of the child classes of both Scene and Object? I am fine with just having two separate watchEvent functions for Scene and Object but how do I pass the type of the Object or the type of the Scene? The child classes are unknown as they are being created by someone using this game engine.
For example, if I want to make a player object it would be something like
class PlayerObject : public Object{...};
Now that PlayerObject type has to find its way to PlayerObject::functionToCall(). I think I need templates to do this but, since I never used them before
This is how I intend to use this
class OtherScene : public Scene{
void p_pressed(void){
//pause
}
[Code].....
If I have an array and all I have is an upper limit on how big the array can get, and if the number of elements that get added can be considerably smaller than this limit, is it always the right choice to declare a pointer and just reallocate extra memory whenever the array grows? For instance, instead of declaring int a[max] I can declare a pointer int *a and than just realloc when I add elements.
View 1 Replies View RelatedThat code should make the size of the pointer (how many chars it can store) bigger but when i run it it show always 3 char positions while it should show N*M.
Code:
#include <stdio.h>#include <stdlib.h>
int main(void) {
int M, N, P, i;
scanf ("%d %d", &M, &N);
P = M * N;
char *c = malloc(P * sizeof(char));
[Code] ....
int hash = 0;
char *strings[100];
if((int)strings[i] != 0)
if((int) strings[hash] != 0)
while((int) strings[hash] != 0)
if((int)strings[hash] != 0)
if((int)strings[hash] != 0)
I have function that looks like this myfoo(char* Name) Now i want to compare this name to another one . But the another name is a pointer . This my code :
bool Tribe::RemoveSurvavior(char *H_Name) {
const char *p;
p=SurpointArr[i]->GetSurvivor_Name();
}
I need to compare if p is same as H_Name.
Mine is do it with for on each element but when i use sizeof it gives me size of char and not real size of the name.
Here is an example,
Code:
class A {
public:
virtual void foo(){}
virtual void foo2(){}
virtual void foo3(){}
};
int main() {
A a;
int ret = sizeof(A);
return 0;
}
Basically object a contains a virtual table pointer which is of size 4 bytes. Since class A should have a virtual table which contains three pointers pointing to foo, foo2,foo3 separately. So the virtual table should be of size 12 bytes. I wonder where is virtual table located in memory?
I'm trying to keep track of the size of blocks of memory that a pointer points to. No matter what I do, this code below always outputs the integer 8.
If I change 1000 to 5, I still get 8. If I change it to 0, I get 8... If I change it to -1, I get 8. If I change int *a to double *a, I get 8. If I take away the & symbol, I get 8. If I use *& instead, I get 8.
Why? I want it to output 1000. If I change that to 500, I want it to output 500.
int *a;
a = malloc(1000 * sizeof(int));
int j = sizeof(&a);
printf("%d", j);
I want to build my skills where I can allocate, inspect and change memory sizes.
how to accommodate double-size:8 bytes in 4 bytes pointer in 32bit system.
View 1 Replies View RelatedI 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] .....
Change the frame window size according to font size increases.
View 3 Replies View RelatedI must take an old MFC project in VC++ 6.0 and make changes.
The problem is text size in screen is different from size in print preview.
for example with this font
Code:
CFont f50;
f50.CreateFont(100,0,0,0,FW_BOLD,0,0,0,DEFAULT_CHARSET,OUT_DEFAULT_PRECIS,
CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,FF_DONTCARE,"Frutiger LT Std 45 Light");
And this text
Code:
s=_T("Let's try to calculate the size of this text");
and with MM_LOMETRIC map mode
GetTextExtent() returns me:
On screen: (1595,99)
Ink printer + print preview: (1589,100)
PDFCreator + print preview: (1580,100)
comparing with screen size the height is bigger but lenght is smaller. I don't understand.
I can understand that different printers process the fonts in different way and then to have different lenghts. That's not the problem. The problem is I need to simulate in screen the same behaviour i will have on printer because these texts are being aligned in the document, and I don't want to see that the text si aligned different in text than in paper.
What can I do to render the text on screen with the same size I will have on the printer? Print preview is doing it. Should I change the font parameters? is something related with pixels per inch?
Is it possible to assign a value to structure member inside the structure.like.....
struct control{
char tbi:2 =0;
char res:1 =0;
};
I was wondering why, in C, the sizeof of a struct is larger than the the sum of all the sizeofs of it's members. It only seems to be by a few bytes, but as a bit of a perfectionist I fine this a bit annoying.
View 1 Replies View Related