Pointer Arithmetic

c pointers pointer-arithmetic
leora picture leora · Dec 27, 2008 · Viewed 88k times · Source

Does anyone have any good articles or explanations (blogs, examples) for pointer arithmetic? Figure the audience is a bunch of Java programmers learning C and C++.

Answer

Jeremy Ruten picture Jeremy Ruten · Dec 27, 2008

Here is where I learned pointers: http://www.cplusplus.com/doc/tutorial/pointers.html

Once you understand pointers, pointer arithmetic is easy. The only difference between it and regular arithmetic is that the number you are adding to the pointer will be multiplied by the size of the type that the pointer is pointing to. For example, if you have a pointer to an int and an int's size is 4 bytes, (pointer_to_int + 4) will evaluate to a memory address 16 bytes (4 ints) ahead.

So when you write

(a_pointer + a_number)

in pointer arithmetic, what's really happening is

(a_pointer + (a_number * sizeof(*a_pointer)))

in regular arithmetic.

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