Void Pointers or Generic Pointers

Void Pointers or Generic Pointers

The void pointer, also known as the generic pointer, is a special type of pointer that can be pointed at objects of any data type. Literal meaning of generic pointer is a pointer which can point any type of data. A void pointer is declared like a normal pointer, using the void keyword as the pointer's type:

void *ptr;

Here ptr is generic pointer. There are some points which should be kept in mind while deal with generic pointer and these are list below:

1. Generic Pointers cannot be dereference

#include<iostream>

using namespace std;

int main()

{

int x=10;

void *ptr;

ptr = &x;

cout<< *ptr;

return 0;

}

The above program output is tested on www.jdoodle.com

Output:

jdoodle.cpp: In function 'int main()':

jdoodle.cpp:8:9: error: 'void*' is not a pointer-to-object type

 cout<< *ptr;

         ^

          or 

compile time error

2. sizeof() operator can be used to check size of Generic Pointers 

#include<iostream>

using namespace std;

int main()

{

int x=10;

void *ptr;

ptr = &x;

cout<< sizeof(ptr);

return 0;

}

The above program output is tested on www.jdoodle.com

Output:  8

3. Generic pointer can hold any type of pointers like char, struct pointer etc without ant typecasting

#include<iostream>

using namespace std;

int main()

{

char ch = 'x';

int i = 2;

void *ptr1;

char *ptr2 = &ch;

int *ptr3 = &i;

ptr1 = ptr2;

cout<< *(char *)ptr2;

cout<<endl;

ptr1 = ptr3;

cout<<*(int *)ptr1;

cout<<endl;

return 0;

}

The above program output is tested on www.jdoodle.com

Output:  

x 

2

Further in Generic pointer are used when we want to return such pointer which is applicable to all types of pointers.

Thanks 

Mukesh Rajput