Character pointers and integer pointers (++)

Question

I have two pointers,

char *str1;
int *str2;

If I look at the size of both the pointers let’s assume

str1=4 bytes
str2=4 byt         


        

Answer 1

Pointer increment always increases the address it points to by the size of the type represented by it. So, for char pointer it increments by 1 and for integer by 4. But, pointer variable itself will require 4 bytes to hold the address.

You can inturn think of how array indexing works. Incase of an integer array a[0] will point to first element and a[1] will point to second. In this case for increment of 1 it should increment by 4 bytes to access the next integer. In case of characters it has to be 1. The same concept works for all pointer arithemtic.

Answer 2

A char is 1 byte, an int is (typically) 4 bytes. When you increment a pointer, you increment by the size of the data being pointed to. So, when you increment a char*, you increment by 1 byte, but when you increment an int*, you increment 4 bytes.

Answer 3

Simple. It depends upon the compiler.

If int has 4 bytes of size when you add 1 to its pointer, it will add its size to it, that is, for and if int is of 2 bytes then it will add 2 that is the size into a pointer. For example, in Turbo C++

int *str = NULL;
str + 1;    //It will add 2 as Turbo C++ has int size 2 bytes

In Visual C++, str+1; //It will add 4 as Visual C++ has int size 4 bytes.

And the same is the case with char.

Answer 4

Simple, in the provided scenario:

• char is 1 byte long
• int (in your platform) is 4 bytes long

The ++ operator increments the pointer by the size of the pointed type.