Mikroelektronika MIKROE-738 Datenbogen

mikroC PRO for PIC32

MikroElektronika

215

Accessing Nested Structures

If the structure 

B

 contains a field whose type is the structure 

A

, the members of 

A 

can be accessed by two applications 

of the member selectors:

struct A {

  int j; double x;

};

struct B {

  int i; struct A aa; double d;

} s, *sptr;

...

s.i = 3;            // assign 3 to the i member of B

s.aa.j = 2;         // assign 2 to the j member of A

sptr->d = 1.23;     // assign 1.23 to the d member of B

sptr->aa.x = 3.14;  // assign 3.14 to x member of A

Structure Uniqueness

Each structure declaration introduces a unique structure type, so that in

struct A {

  int i,j; double d;

} aa, aaa;

struct B {

  int i,j; double d;

} bb;

the  objects 

aa

  and 

aaa

  are  both  of  the  type  struct 

A

,  but  the  objects 

aa

  and 

bb

  are  of  different  structure  types. 

Structures can be assigned only if the source and destination have the same type:

aa = aaa;    /* OK: same type, member by member assignment */

aa = bb;     /* ILLEGAL: different types */

aa.i = bb.i;

aa.j = bb.j;

aa.d = bb.d;