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<h4 class="subsection">6.2.1 <code>STRUCTURE</code> and <code>RECORD</code></h4>
<p><a name="index-g_t_0040code_007bSTRUCTURE_007d-325"></a><a name="index-g_t_0040code_007bRECORD_007d-326"></a>
Structures are user-defined aggregate data types; this functionality was
standardized in Fortran 90 with an different syntax, under the name of
“derived types”. Here is an example of code using the non portable
structure syntax:
<pre class="example"> ! Declaring a structure named ``item'' and containing three fields:
! an integer ID, an description string and a floating-point price.
STRUCTURE /item/
INTEGER id
CHARACTER(LEN=200) description
REAL price
END STRUCTURE
! Define two variables, an single record of type ``item''
! named ``pear'', and an array of items named ``store_catalog''
RECORD /item/ pear, store_catalog(100)
! We can directly access the fields of both variables
pear.id = 92316
pear.description = "juicy D'Anjou pear"
pear.price = 0.15
store_catalog(7).id = 7831
store_catalog(7).description = "milk bottle"
store_catalog(7).price = 1.2
! We can also manipulate the whole structure
store_catalog(12) = pear
print *, store_catalog(12)
</pre>
<p class="noindent">This code can easily be rewritten in the Fortran 90 syntax as following:
<pre class="example"> ! ``STRUCTURE /name/ ... END STRUCTURE'' becomes
! ``TYPE name ... END TYPE''
TYPE item
INTEGER id
CHARACTER(LEN=200) description
REAL price
END TYPE
! ``RECORD /name/ variable'' becomes ``TYPE(name) variable''
TYPE(item) pear, store_catalog(100)
! Instead of using a dot (.) to access fields of a record, the
! standard syntax uses a percent sign (%)
pear%id = 92316
pear%description = "juicy D'Anjou pear"
pear%price = 0.15
store_catalog(7)%id = 7831
store_catalog(7)%description = "milk bottle"
store_catalog(7)%price = 1.2
! Assignments of a whole variable don't change
store_catalog(12) = pear
print *, store_catalog(12)
</pre>
<!-- @node UNION and MAP -->
<!-- @subsection @code{UNION} and @code{MAP} -->
<!-- @cindex @code{UNION} -->
<!-- @cindex @code{MAP} -->
<!-- For help writing this one, see -->
<!-- http://www.eng.umd.edu/~nsw/ench250/fortran1.htm#UNION and -->
<!-- http://www.tacc.utexas.edu/services/userguides/pgi/pgiws_ug/pgi32u06.htm -->
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