Toolkit Tutorial: Programming



  
dt_Handle
 
atom1
,
 
atomX
;

  

dt_Integer
 
number
,
 
slen
,
 
charge
;

  

dt_String
 
symbol
;


  

/* next item gives the first atom */

  

atom1
 
=
 
dt_next
(
container
);

  

number
 
=
 
dt_number
(
atom1
);

  

symbol
 
=
 
dt_symbol
(
&
slen
,
 
atom1
);

  

charge
 
=
 
dt_charge
(
atom1
);

  

printf
(
"The atom number is %d, the symbol is \"%.*s\", "

      

"and the charge is %d.\n"
,
 
number
,
 
slen
,
 
symbol
,
 
charge
);


  

/* The next item gives the second atom. */

  

atomX
 
=
 
dt_next
(
container
);

  

number
 
=
 
dt_number
(
atomX
);

  

symbol
 
=
 
dt_symbol
(
&
slen
,
 
atomX
);

  

charge
 
=
 
dt_charge
(
atomX
);

  

printf
(
"The atom number is %d, the symbol is \"%.*s\", "

      

"and the charge is %d.\n"
,
 
number
,
 
slen
,
 
symbol
,
 
charge
);


  

/* The next item is the NULL object. */

  

atomX
 
=
 
dt_next
(
container
);

  

if
 
(
NULL_OB
 
==
 
atomX
)

    

printf
(
"The NULL object is next.\n"
);


  

/* A reset and next operation gives the first atom again. */

  

dt_reset
(
container
);

  

atomX
 
=
 
dt_next
(
container
);

  

if
 
(
atomX
 
==
 
atom1
)

    

printf
(
"Reset is like rewind.\n"
);


  

/* Each atom refers to the molecule as its parent. */

  

if
 
(
dt_parent
(
atomX
)
 
==
 
molecule
);

    

printf
(
"You can access the molecule through the atom\n"
);