Are Pointer Sizes Fixed or Dependent on the Data Type They Point To?

The Size of Pointers: A Fixed Value or Dependent on Type?

In programming, a pointer is a variable that stores the memory address of another variable. A common question arises: is the size of a pointer the same as the size of the type it points to, or do pointers always have a fixed size?

To demonstrate, consider the following code:

int x = 10;
int * xPtr = &x;
char y = 'a';
char * yPtr = &y;

std::cout << sizeof(x) << "\n";
std::cout << sizeof(xPtr) << "\n";
std::cout << sizeof(y) << "\n";
std::cout << sizeof(yPtr) << "\n";

This code outputs the following:

4
4
1
4

As you can see, both pointers, xPtr and yPtr, have a size of 4 bytes, regardless of the size of the variables they point to. This is because pointers generally have a fixed size, determined by the memory model of the system. In this case, the system likely follows a 32-bit executable model.

While most systems use a fixed size for pointers, there are exceptions. For instance, in older 16-bit Windows systems, there were 32-bit and 16-bit pointers that had different sizes.

However, it's essential to note that making assumptions about pointer sizes in your code should be avoided. Instead, if you require specific pointer sizes, you should verify it explicitly through appropriate methods.

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