What I'm trying to do is:
int *p;
someType memoryLocation;
cout<<"Enter your memory location: ";
cin >> memoryLocation;
p = memoryLocation;
cout << *p;
I was just messing around with some code, and was curious to if this was possible.
I have an integer pointer and i want its address without allocating memory,
main() {
int *a;
cout<<a;
}
This is giving 00000000 and its but obvious. Now if i use address of a (&a) along with *a,
main() {
int *a;
cout<<a;
cout<<&a;
}
'cout<<a' gives me a constant address but 'cout<<&a' gives me different address.
what is the reason behind & and why behaviour of 'cout<<a' changes when using with &.
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:
int instance_new(std::vector<uintptr_t> &instance_id, unsigned &instance_size, Instance *pointer) {
instance_id[instance_size] = reinterpret_cast<std::uintptr_t>(pointer);
instance_size++;
instance_id.resize(instance_size);
return 0;
}
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?
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??
Code:
#include <stdio.h>
#include <stdlib.h>
typedef struct node{
int num;
struct node* next;
}Node, *NodePtr;
}
[code]....
I am working on an assignment for class: Create a program that allows a user to enter up to 10 addresses of friends. Use a two dimensional array to store the address of friends. After each address is entered, the user should have the option to enter another address or print out a report that shows each addresses entered thus far. I have created a code that is coming up without errors, but i am not getting the desired results.
Code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main ()
{
char name[10][10] = {0};
char address[10][10]= {100};
int choice;
[Code]....
My trouble is coming from the the output. I am able to fill the array but i am not able to print my desired results. Where am I losing it in the loop? Also after my first entry if i have space in the "address" input the program prints and ends.
I have written a C program without variable. And I want to print the value at that memory location.How to print that value?
code is like:-
int main()
{
printf("Enter value:");
scanf("%d",1245024);
/* how to print the value here */
return 0;
}
I am working on something that requires the memory address of my computers workload.. collect the trace files? and what trace file as well..
View 2 Replies View RelatedPointers point to an address in memory. What if I used 3 pointers: 2 to mark the first/last nodes, and the third to mark the current node being referenced? I would wrap it in a class (to make the memory management automatic, of course), but is this practical?? maybe some pseudo code will get the juices flowing:
template<class type>
class supercondensed_list{
public:
supercondensed_list();
~supercondensed_list();
[code].....
Any things I should take into consideration? I'm not exactly the most experienced with pointers, and manually managing memory, but I think it's worth trying. If this works, then my programs should, in theory, be 100% memory efficient.
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.
For example:
char name[] = {"Hello"}; // | 'H' | 'e' | 'l' | 'l' | 'o' | '/0' |
An address holds the value of 'H'.
An address holds the value of 'e'.
An address holds the value of 'l' and so on.
I have come to believe this is false, however. Mainly from a simple std::cout command.
std::cout << &name << std::endl; // attempt 1
std::cout << &name[0] << std::endl; // attempt 2
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?
The results of my code is supposed to be very simple: return the 2 integers and then their sum. However, it's doing returning the first value, then an address in memory(rather than the 2nd value), and then the 2nd value(rather than the sum). Here is the code:
#include <stdio.h>
#include <stdlib.h>
struct calculator{
double num1;
double num2;
double result;
[Code] .....
I made a text file. I can do all File I/O functions in c. no problem! except that "I want to get the memory address of the beginning of that File", so that I can access each character of the file by incrementing memory address.
View 1 Replies View RelatedA special hardware unit with some storage in it is connected to your computer and is memory-mapped so that its storage is accessible in the address range 0x55500000 – 0x555fffff. You want to interface this hardware unit to your C++ program so that dynamic memory is allocated in this hardware unit, not in your computer’s memory. Implement a class MyHardwareMemAllocator which has the following function.
void * allocMemoryInMyHardware(int numberOfBytesToAllocate);
which returns a pointer to the allocated memory chunk, or null if unable to allocate.
C library calls like malloc are not allowed.
1) How to allocate memory from given address range.
2) How to check whether this required memory space is available or not for allocating
Suppose I have two classes, MyClassX and MyClassY, each with two member variables, as defined below. I create an object instance of each class, and then create a pointer to each member variable for each object:
Code:
class MyClassX
{
public:
int a;
double b;
MyClassX(int _a, double _b)
[code]....
After converting the hexadecimal to decimal, it appears that with MyClassX, pxb is 8 bytes from pxa, whereas for MyClassY, pya is only 4 bytes from pyb. This makes sense for MyClassY, because the first member variable to be stored is an int, and so will occupy 4 bytes. However, why should this be any different for MyClassX, which also has an int as the first member variable, so shouldn't this also occupy 4bytes?
The reason I have come across this problem is that I am looking into streaming objects to memory and then loading them again. (I know boost can do this, but I am trying it out myself from scratch.) Therefore, this is causing an issue, because I cannot just assume that the size of memory occupied by an object is just the sum of the sizes of its member variables. MyClassX is 8 bytes larger than MyClassY, even though the intuition is that it should only occupy 4 bytes more due to a double being replaced by an int.
I'm making a system like twitter for class called ShoutOut.com I want to be able to get the PublicShoutOut pointer pointed to by the start iterator and assign it to firstShoutOutToDisplay and secondShoutOutToDisplay because I need that in order to pass the pointers to one of my functions. When I step through the debugger the values in start are all default values like "" and so are the values in this->firstShoutOutToDisplay but the message that start points to is being output just fine.
EDIT: got rid of irrelevant code. Am I using the correct syntax to do this?
if (start != finish) {
//getting these because a shoutout needs to be passed to the function that displays
//options for a shoutout
this->firstShoutoutToDisplay = (*start);
[Code] ....
I want to store the address of a customer (with spaces) in a char variable (say cadd). First I tried to use "cin", as we know it reads until it sees any whitespace. So it reads only first word before a white space. So, I used "getline()" function, it will work. But when I used it, It did'nt wait for the I/P (it skipped it).
char cadd[20];
std::cout<<"Enter Customer Address:
";
std::cin>>cadd;
std::cout<<"Enter Customer Address:
";
std::cin.getline(cadd,20);
When declaring char array[10], memory is allocated for 10 1-bit memory locations. Is extra memory allocated for storing the address of array[0]? In expressions, is array equivalent to a pointer constant or is it an identifier for a memory cell containing the address of array[0]? In other words, is array a variable or an alias for &array[0]?
View 6 Replies View RelatedTry to implement overloading << operator. If I done it void then everything work fine (see comment out) if I make it class of ostream& then the operator return to me some memory address.
Code:
#ifndef Point_HPP // anti multiply including gates
#define Point_HPP
#include <sstream>
class Point {
private:// declaration of private data members
double x;// X coordinate
double y;// Y coordinate
[Code] .....
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.
I have a pointer to an Address is there a way to save that address value (not the content but the actual address) into a char ?
View 5 Replies View RelatedI have the following code.
StackElement *StackElementArray;
StackElementArray = new StackElement[iMaximumDepth];
I want to assign one element of this array StackElementArray the address of another object. For example,
voidStackMem::push(StackElement &iStackElement) {
CurrentDepth++;
StackElementArray[0] = iStackElement;
}
The StackElement class contains pointers to some dynamic arrays. When I use the assignment, StackElementArray[0] = iStackElement;, it doesn't copy the complete contents and I have to define an 'assignment operator' function to copy all the contents. I am wondering if there is a way I can assign StackElementArray[0] the pointer to the StackElement object. In that case, I will not need to copy the contents of iStackElement into StackElementArray[0] and will just copy the address.
#include <iostream>
using namespace std;
void myfunc(int* ); // what do i put in these parameters to accept a mem loc of a pointer
int main () {
int x = 5;
[Code] .....
SOLUTION:
#include <iostream>
using namespace std;
//Purpose to create a function that returns a pointer to a pointer
int** myfunc(int**);
int main () {
int x = 5;
[Code] ....
Why my pointer skips over the colour addresses, it jumps to the next size address when I use Pointer++. I have tried changing the the char array to 4 bytes instead of 32 and whatnot but it doesn't work.
If I set the Pointer = the first colour address, it skips over the size addresses and only get the colour addresses. I know using 2 arrays would easily solve everything, but sadly I must use only 1.
I'll post whatever relevant code here:
For part of my program in class I have to take a pointer address and determine if it is equal to 0 modulus 16. But I can't figure it out.
View 1 Replies View RelatedI need to initialize a pointer variable with a knowing address. See code below, ptr is the final destination and value of ptr_address contains the address value, so I need to do something like ptr = *ptr_address.
Code:
int *ptr;
int *ptr_address;
int address;
address = 0x10000005;
ptr_address = &(address);
ptr = *ptr_address;
The problem is that compiler gives the following warning message:
warning: assignment makes pointer from integer without a cast [enabled by default]
Is my code wrong or there is any other way to do it without receiving this compiler warning?
Is there such thing as passing a winforms label by reference? For example, can I create a pointer label and pass the address to a function? I've looked online but couldn't find anything. Perhaps that's a sign?
View 1 Replies View RelatedI have one requirement to store an array of structure at shared memory. Also the shared memory should have one counter to store number of elements in the array.
I tried to look at some placed but didn't find anything relevant.
So my first question, is it possible that we can store two things on same shared memory. And second if not then how to achieve the same?