lec4 :: Pointer Arithmetic

Pointer Arithmetic
Increment operator when used with a pointer variable returns next address pointed by the pointer. The next address returned is the sum of current pointed address and size of pointer data type. Or in simple terms, incrementing a pointer will cause the pointer to point to a memory location skipping N bytes from current pointed memory location. Where N is size of pointer data type.
Similarly, decrement operator returns the previous address pointed by the pointer. The returned address is the difference of current pointed address and size of pointer data type.
For example, consider the below statements::
int num = 5; // Suppose address of num = 0x1230
int *ptr; // Pointer variable
ptr = # // ptr points to 0x1230 or ptr points to num
ptr++; // ptr now points to 0x1234, since integer size is 4 bytes
ptr--; // ptr now points to 0x1230


Note: Increment operation increments pointer address by the size of pointer data type.
If an integer pointer ptr pointing at 0x1230, after ptr++ it will point at 0x1234(assuming integer size is 4 bytes).
If a character pointer cptr pointing at 0x1250, after cptr++ it will point at 0x1251(since character occupies 1 byte).