C Pocket Reference

Memory Accessing Operators

The operators in Table 1-14 are used to access objects in memory. The terms used here, such as pointer, array, structure, etc., are introduced later under Section 1.10.

Table 1-14. Memory accessing operators

Operator	Meaning	Example	Result
&	Address of	&x	A constant pointer to x
*	Indirection	*p	The object (or function) pointed to by p
[ ]	Array element	x[i]	*(x+i), the element with index i in the array x
.	Member of a structure or union	s.x	The member named x in the structure or union s
->	Member of a structure or union	p->x	The member named x in the structure or union pointed to by p

The operand of the address operator & must be an expression that designates a function or an object. The address operator & yields the address of its operand. Thus an expression of the form &x is a pointer to x. The operand of & must not be a bit-field, nor a variable declared with the storage class specifier register.

The indirection operator * is used to access an object or a function through a pointer. If ptr is a pointer to an object or function, then *ptr designates the object or function pointed to by ptr. For example:

int  a, *pa;  // An int variable and a pointer to int. 

pa  = &a;     // Let pa point to a. 
*pa = 123;    // Now equivalent to  a = 123;

The subscript operator [] can be used to address the elements of an array. If v is an array and i is an integer, then v[i] denotes the element with index i in the array. In more general ...