void pointer in C

A void pointer is a pointer that has no associated data type with it. A void pointer can hold address of any type and can be typcasted to any type.int a = 10;
char b = ‘x’;

void *p = &a; // void pointer holds address of int ‘a’
p = &b; // void pointer holds address of char ‘b’Advantage of void pointers:malloc() and calloc() return void * type and this allows these functions to be used to allocate memory of any data type (just because of void *)int main(void)
{
// Note that malloc() returns void * which can be
// typecasted to any type like int *, char *, ..
int *x = malloc(sizeof(int) * n);
}Note that the above program compiles in C, but doesn’t compile in C++. In C++, we must explicitly typecast return value of malloc to (int *).Some Interesting Facts:1) void pointers cannot be dereferenced. For example the following program doesn’t compile.int main()
{
int a = 10;
void *ptr = &a;
printf(“%d”, *ptr);
return 0;
}Output:Compiler Error: ‘void*’ is not a pointer-to-object typeThe following program compiles and runs fine.int main()
{
int a = 10;
void *ptr = &a;
printf(“%d”, *(int *)ptr);
return 0;
}Output:102) The C standard doesn’t allow pointer arithmetic with void pointers. However, in GNU C it is allowed by considering the size of void is 1. For example the following program compiles and runs fine in gcc.int main()
{
int a[2] = {1, 2};
void *ptr = &a;
ptr = ptr + sizeof(int);
printf(“%d”, *(int *)ptr);
return 0;
}Output:2

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