So I obviously can't take the address of a bitfield, but is there a way to get the address of the field holding the bitfield? What I'm trying to do is find the address of the parent field of a bitfield in a class. For example
Code:
class Foo
{
public:
int a;
int b : 4;
int c : 28;
[Code] ....
My goal is to get the offset address of the int storing c in class Foo. But offsetof uses the address of c, so I get a compile error since c is a bitfield. What I wanted as output from the above would be "4", since an int is 4 bytes (on my system). So the int holding both b & c starts 4 bytes from the start of the Foo class. Is there any way to do this in c/c++?
I've recently been reading tutorials on arrays and their aquaintance with memory addresses. So, I completely understand how an array's name, when defined, is a constant pointer to its first element's address.
My problem, however, lies with characters, and how they are basically arrays except with a null terminator for the last index. What I've come to undestand, is that, when defining a character variable, each 'character' has a memory address it is associated with.
The first attempt, as I assumed, should print the address of the first element. The second attempt, as I assumed, did not. I figured, &names[0] would print the address of the first element, which should have been the same as &names.
So, this brings me to my question, are characters formed of constant addresses, or are the address of individual characters not reachable?
I'm currently working with linear VRAM (a buffer with 256KB memory, divided into four 64k planes, so plane 0 at 0x00000, plane 1 at 0x10000, plane 2 at 0x20000, plane 3 at 0x30000). Just add the index of the plane to that for the full address in VRAM.
I'm still wondering how to get a specific pixel from VRAM (x,y coordinate) when doing graphic modes (none color modes work, only the black/white pixels (1-bit) graphic mode works).
how I can get specific pixels from the VGA VRAM (having linear access described above) using Shift Register Interleave mode (VGA modes 4&5), 16-bit planar mode (Most VGA modes) etc.
I'm wondering what is the "best" way to initialize a bitfield struct. I have this bitfield, defined as:
Code: struct S { unsigned int a : 1; unsigned int b : 1; };
If I'm "using" the bitfield, I can initialize it easily when declaring it, as so:
Code: int main() { S s = {0}; }
Now, the issue I'm facing is that I want to embed S inside another struct, which I'll name "outer". EG:
Code: struct Outer { S s; };
I'm wondering what the "best" way to have Outer initialize S is? I've seen a lot of people use the "union" approach:
Code: struct Outer { Outer() { u.all = 0; } union { unsigned char all; S s; } u; };
but:This adds an extra field depth (the union's u)Does bit hacking, in a way (is the bitfield as large as my field?) I'd have wanted to initialize the field in my constructor, as so:
Code: Outer::Outer() : s({0})
However, this would appear to be a C++11 feature only.
I have, however, "observed" that by simply "empty constructing" s, eg:
Code: Outer::Outer() : s(){} //Initialize s ? vs Outer::Outer(){}
BIT_FIELD_TYPE; Except, what I'd like to do is to replace all the single-bit elements in the bits structure with a single statement that creates an array of, say, 32 values. The clear advantage of this is that it could be traversed using an iterator, ...
Code: main() { BIT_FIELD_TYPE foo; unsigned int i; ... for (i = 0; i < n; i++) { ... (print out foo.bits.b[i]) ... }
So far, I've not figured out a way to do it, either as an array, or using a pointer to iterate through the individual bits.
I've run across this issue before, but for the like of me, I can't figure out what keeps causing it. The problem compiles and runs as expected; however in the salaried object (Employee #1 in main.cpp) the console displays the number of vacation days as -858993460 instead of the value entered.
The parent Employee class is abstract with calculatePay() and displayEmployee() being pure virtualls and with a Benefits, Salaried, and Hourly class derived from it.
The Salaried displayEmployee() and the portion of the Main.cpp that contains the salaried object follows. What causing this?
I've got a problem with a piece of code that it doesn't seem to work anymore.
Code: #include <stdio.h> #include <conio.h> main () {
[Code] ..... i
I chose a to be 5 and it displays the following:
"Type a value for a: 5 5 in octal is: 5 5 in hexadecimal is: 5
Process returned 23 <0x17> execution time : 1.031 s".I first saw this when trying to display the address of a pointer. Am i missing something? I used to run this code on dev-c++ successfully but after a day or so of practice, it's not working anymore. I switched from dev-c++ to code blocks.
So im trying to parse a string into a Ip Address but i have a problem, the IPAddress.Parse method only works for ipv4 address's how do i parse ANY Ip address into a string, if i use the IPaddress.Parse method on my public(remote) IP it throws an exception but on ipv4 local ip it doesn't how do i parse ANY ip address the user inputs as a string as an Ip Address?
I'm using the SDL library and trying to match the C++11 standards... Anyway, I thought about a vector where I store all the addresses of game instances, so I can access them anytime... I tried with this function:
Where "Instance" is the 'parent' class of various child classes like the player. So, if I have to search the existing of a thing in my game, I should check if the address references to an instance of class. How can I do this?
When this programs runs it displays odd symbols for the address of the character. This is only part of the program, I took out the parts that already work.
#include <iostream> using namespace std; char again;
I'd like a function to return either a value or the address of that value by the users input. So he can call the function like:
function("adress") - gets an adress, or function("value") - gets the value
I've tried both function overloading and templates, but none of them worked. He might input a character for the address and an int for the value... but...
Another strange thing that i observed is that the value returned by the function below is 0, so the output is address 0.
Reversing Linklist using Stack. I have created linklist using <list> STL. Now I want to push address of each node in Stack. For that I want address of 1st node so that I will assign it to "temp" and I can use following loop.
HTML Code: while (temp != NULL) { s.push(temp); temp = temp->next; }
But I am not getting address of 1st node. I tried function l1.front() which gives 1st element but not address.
You can return values from functions by ref, address or value you can also do this with parameters, so what is the difference, if you have full return of a passed parameter by ref or address why would you need to ever return the function as a whole?
For ex Code: int nValue(int& y){ y++; } or int& nVlaue(int y){ return y; }
This program is an address book where you caan add/view entries. I'm having a problem printing out entries. Why the information isn't getting saved into the structure array?
Code: #include <iostream> #include <string> using namespace std; struct contactinfo
I'm reading through a data structure textbook. I'm doing the part of Linked list. here's the code from the textbook:I'm not clear with pointer.what I'm confused is that the code created a pointer to the structure (*NodePtr)
Q1. Is NodePtr store the address of the structure?? Q2. Are top, np, last address of the structure?? Q3. here.....NodePtr makeNode(int);... does it returns an address of the structure which is np?? but following part np is used as a pointer??
