Pointers & Arrays

Pointers & Arrays

Arrays and pointers are nearly twins in C: an array name "decays" to a pointer to its first element.

The array name is a pointer

int a[] = {10, 20, 30};
int *p = a;        // same as &a[0]
printf("%d", *p);  // 10, the first element

Pointer arithmetic moves between elements

a[0]     -> *p
a[1]     -> *(p + 1)

a[2]     -> *(p + 2)

Adding 1 to the index moves one element forward (not one byte!).

The classic equivalence

a[i] is the same as *(a + i). Welcome to pointer math.

TL;DR

• The array name acts as a pointer to its first element.
• p + i points to element i.
• To index: a[i] and *(a + i) are identical.
• Increments move by element size, not by byte.