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Meaning c plus plus pointer to an array and pointer to a structure?
Wiki User
∙ 11y ago
They both mean the same thing; an array is a type of data structure (a linear structure). A pointer variable is just a variable like any other, but one that is used to specifically store a memory address. That memory address may contain a primitive data type, an array or other data structure, an object or a function. The type of the pointer determines how the data being pointed at is to be treated. Pointers must always be initialised before they are accessed, and those that are not specifically pointing at any reference should always be zeroed or nullified with the NULL value. This ensures that any non-NULL pointer is pointing at something valid. Remember that pointer variables are no different to any other variable insofar as they occupy memory of their own, and can therefore point to other pointer variables.
Wiki User
∙ 11y ago
Wiki User
∙ 9y ago#include<iostream>
struct s
{
// ...
};
int main()
{
s* p = new s;
// ...
delete p;
}
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How arrays must be handled in c plus plus?
If the array is static it can declared in the structure itself: struct myArrayTag { int num[12]; // array of 12 integers (e.g., 48 bytes). } myArray; If it is dynamic then you must use a pointer and allocate the array outside the structure. You should also maintain a variable in the structure to keep track of how many elements the array currently has: struct myBufferTag { int * array; // Pointer to array of integers. int size; // Size of array (number of elements); } myBuffer;
Delete memory release operator in c plus plus?
You can't physically delete memory, you can only delete a pointer to allocated memory, which subsequently releases the memory back to the system. The operator is delete, passing the pointer as the operand. If the pointer points to an array, then you must also use the index operator [] in front of the pointer name.int main(){// pointer to an int type with value 100int* ptr_int = new int(100);// ... use pointer ...// release the integerdelete ptr_int;// pointer to an array 100 int types (with undefined values)int* ptr_int_array = new int[100];// ... use array ...// release the arraydelete [] ptr_int_array;return(0);}
Are structures and pointers related in c plus plus?
Not really, but you can have: - a pointer pointing to a structure (FILE * is an example) - a pointer pointing to a structure-member (eg: struct tm tm; int *ip= &tm.tm_year) - a structure-member that is a pointer (any type) Example: typedef struct TreeNode { struct TreeNode *left, *right; int data; } TreeNode; TreeNode *root = (TreeNode *)calloc (sizeof (TreeNode), 1);
What is Dazzling Pointer in c plus plus?
The pointer that points to a block of memory that does not exist is called a dazzling pointer or wild pointer
When is memory allocated when declaring an array in C plus plus?
It depends how the array is declared (fixed size or variable size) and where it is declared (global scope or local scope). If the array is declared in global scope (outside a function) and is fixed size, it will be allocated in static memory. If it is variable size, the pointer is stored in static memory while the array itself is allocated on the heap. The pointer in static memory points to the start address of the array in heap memory. If the array is declared in local scope (inside a function) and is fixed size, it will be allocated on the stack in whichever thread the function was called. If it is variable size, the local pointer is stored on the stack while the array is allocated on the heap. The pointer will fall from scope when the function returns so the array must not be allowed to outlive the function in which the pointer is declared. If the array must outlive the function that allocates the array, the pointer must be declared at a higher scope in the call stack and must be passed by reference to or returned by value from the function that allocates the array. If you provide your own memory manager, however, an array may be allocated wherever the memory manager's memory pool is allocated, be it in static memory, the stack or the heap. A memory manager essentially allocates an array of bytes which you can then utilise as you see fit (the array of bytes will be allocated as per the previous description for arrays in general).
How arrays must be handled in c plus plus?
If the array is static it can declared in the structure itself: struct myArrayTag { int num[12]; // array of 12 integers (e.g., 48 bytes). } myArray; If it is dynamic then you must use a pointer and allocate the array outside the structure. You should also maintain a variable in the structure to keep track of how many elements the array currently has: struct myBufferTag { int * array; // Pointer to array of integers. int size; // Size of array (number of elements); } myBuffer;
How do you declare a string array and add elements to it in C plus plus?
You cannot add elements to a fixed array in C or C++. If, however, the array is declared as a pointer to an array, you can add elements by allocating a new array, copying/adding elements as needed, reassigning the new array to the pointer, and deallocating the original array.
Searching array element by using pointer in c plus plus?
The name of an array can be looked as a pointer of this array,and it points to the local memory address of the first element.So we can gave the address to a pointer.The flow is an easy example to show hou to use a pointer to print an array.#include "iostream.h"void main(){char a[]="abcdefgh";char *b=a;//afor(int i=0;i
Why pointer is used to reference a string of characters write C plus plus statements that display the text hello using pointer to a string notation?
We use a pointer to reference a string because a string is an array of characters where every element is a char (or a wchar_t if using UNICODE strings). Passing arrays by value would require the entire array to be copied, but passing a pointer variable to an array only copies the pointer, which is effectively the same as passing the array by reference. #include <iostream> int main() { char * psz = "hello"; // pointer to a null-terminated string. std::cout << psz; // pass the pointer (by value) to the insertion operator. return( 0 ); }
Delete memory release operator in c plus plus?
You can't physically delete memory, you can only delete a pointer to allocated memory, which subsequently releases the memory back to the system. The operator is delete, passing the pointer as the operand. If the pointer points to an array, then you must also use the index operator [] in front of the pointer name.int main(){// pointer to an int type with value 100int* ptr_int = new int(100);// ... use pointer ...// release the integerdelete ptr_int;// pointer to an array 100 int types (with undefined values)int* ptr_int_array = new int[100];// ... use array ...// release the arraydelete [] ptr_int_array;return(0);}
When does an array behave like a pointer in C plus plus -- provide sample code to support each case?
An array never behaves like a pointer.Understand that a pointer is a variable -- no different to any other variable, other than its type. like any other variable, it is allocated its own memory (4 bytes in a 32-bit system). Those 4 bytes can store any 32-bit value, from 0x00000000 to 0xFFFFFFFF, but because it is declared to be a pointer, that value actually represents a memory location, somewhere within the 4GB address space. 0x00000000 is a reserved memory location -- what we refer to as NULL.An array is not the same as a pointer in any sense. The array name refers to the actual memory (the starting address) where the array resides. But the array name is not a variable -- unlike a pointer, it is not separate from the memory it refers to -- it is merely an alias that refers to the memory allocated to the array itself.That said, pointers and arrays can appear to be the same. For instance, the strlen() function expects you to pass a const char pointer, and yet you can pass an array name instead and it works just fine:char cArray[12];char * p = cArray;strlen( p ); // Pass a pointerstrlen( &cArray[0] ); // Pass pointer to array element via AddressOf operatorstrlen( cArray ); // Pass an array nameAll three of these functions work exactly the same so it would be easy to assume the array is a type of pointer. But it is not. To understand what's really going on here you have to understand how pointers and arrays are actually passed to function.When you pass a pointer to a function, you don't pass the pointer itself, you pass the memory address stored in the memory allocated to the pointer. In other words, pointers are passed by value, not by reference. Similarly, when you pass an array name, you pass the starting address of the array.That's all there is to it! The function's parameter, a pointer, is allocated its own memory. It is a temporary variable, local to the function. All it expects is a memory location so whether you pass a pointer or an array name, that's exactly what it receives.
Are structures and pointers related in c plus plus?
Not really, but you can have: - a pointer pointing to a structure (FILE * is an example) - a pointer pointing to a structure-member (eg: struct tm tm; int *ip= &tm.tm_year) - a structure-member that is a pointer (any type) Example: typedef struct TreeNode { struct TreeNode *left, *right; int data; } TreeNode; TreeNode *root = (TreeNode *)calloc (sizeof (TreeNode), 1);
What is Dazzling Pointer in c plus plus?
The pointer that points to a block of memory that does not exist is called a dazzling pointer or wild pointer
When is memory allocated when declaring an array in C plus plus?
It depends how the array is declared (fixed size or variable size) and where it is declared (global scope or local scope). If the array is declared in global scope (outside a function) and is fixed size, it will be allocated in static memory. If it is variable size, the pointer is stored in static memory while the array itself is allocated on the heap. The pointer in static memory points to the start address of the array in heap memory. If the array is declared in local scope (inside a function) and is fixed size, it will be allocated on the stack in whichever thread the function was called. If it is variable size, the local pointer is stored on the stack while the array is allocated on the heap. The pointer will fall from scope when the function returns so the array must not be allowed to outlive the function in which the pointer is declared. If the array must outlive the function that allocates the array, the pointer must be declared at a higher scope in the call stack and must be passed by reference to or returned by value from the function that allocates the array. If you provide your own memory manager, however, an array may be allocated wherever the memory manager's memory pool is allocated, be it in static memory, the stack or the heap. A memory manager essentially allocates an array of bytes which you can then utilise as you see fit (the array of bytes will be allocated as per the previous description for arrays in general).
What is an ordered list of data structure using c plus plus?
An ordered list of data in any programming language is simply a sorted array or list. In C++ this can either mean a sorted array, vector, list or forward list.
What is the meaning of star d in c plus plus programming?
If d is a pointer variable, then *d is the value stored in the memory address pointed to by d.
Program in c plus plus to delete an element in sorted array?
If the array is dynamic then use a vector instead of an array. You can then use the vector::erase() function to delete an element or a range of elements. Remember that if the vector contains pointers to unshared memory, then you must release the pointer before erasing the element containing that pointer. If the array is static then you cannot delete elements. The assumption with static arrays is that you will neither add nor delete, you will only modify existing elements. However, you can emulate a deletion by shunting elements to the left, and keeping track of how many used elements there are (which must always be less than or equal to the upper bound plus one). Again, if the array contains pointers to unshared memory, you must release the pointer before shunting elements. You can also do the same thing with dynamic C-style arrays, but once you've shunted elements to the left you can reallocate the array with the new size to physically delete the final element.
