Void pointer

In c++, we can’t assign the address of a variable of one data type to a pointer of another data type.

In such a case, use a void pointer or generic pointer.

Facts:

1. malloc() and calloc() returns void * type and allow this function to be used to allocate memory of any data type.
2. void pointers are used to implement a generic function in c.
3. void pointer can’t be dereferenced.

int main() {
    int a = 10;
    void *ptr = &a;
    printf("%d", *ptr);
}

Output:

compile error: void* is not pointer-to-object type

4. void pointer doesn’t allow pointer arithmetic.

Program:

#include <iostream>
using namespace std;
int main()
{
    void *ptr1;
 
    struct student {
        int a;
        int b;
    };
    struct student *stud_ptr;
   
    stud_ptr->a = 10;
    stud_ptr->b = 20;
ptr1 = (struct student *)malloc(sizeof(student));
    ptr1 = stud_ptr;
    printf("%d\n", (*(student *)ptr1).a);
return 0;
}

Output

10