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Pointers and Structures

These are fairly straight forward and are easily defined. Consider the following:

struct COORD {float x,y,z;} pt;

struct COORD *pt.ptr;

*pt.ptr = &pt;        /* assigns pointer to pt */

the operator lets us access a member of the structure pointed to by a pointer.i.e.:

pt_ptrx = 1.0;

pt_ptry = pt_ptry - 3.0;

Example: Linked Lists

typedef struct { int value;

ELEMENT *next;

} ELEMENT;

ELEMENT n1, n2;

n1.next = & n2;

Linking Two Nodes

NOTE: We can only declare next as a pointer to ELEMENT. We cannot have a element of the variable type as this would set up a recursive definition which is NOT ALLOWED. We are allowed to set a pointer reference since 4 bytes are set aside for any pointer.

The above code links a node n1 to n2 We will look at this matter further in the next Chapter.