Difference between revisions of "Records"

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m (Text replace - "delphi>" to "syntaxhighlight>")
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To declare a record, you'd use:
 
To declare a record, you'd use:
<delphi>
+
<syntaxhighlight>
 
TYPE
 
TYPE
 
   TypeName = record
 
   TypeName = record
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     identifierlistn : datatypen;
 
     identifierlistn : datatypen;
 
   end;
 
   end;
</delphi>
+
</syntaxhighlight>
  
 
For example:
 
For example:
<delphi>
+
<syntaxhighlight>
 
type
 
type
 
   InfoType = record
 
   InfoType = record
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     Zip : integer;
 
     Zip : integer;
 
   end;
 
   end;
</delphi>
+
</syntaxhighlight>
  
 
Each of the identifiers <tt>Name, Age, City, State</tt>, and <tt>Zip</tt> are referred to as fields. You access a field within a variable by:
 
Each of the identifiers <tt>Name, Age, City, State</tt>, and <tt>Zip</tt> are referred to as fields. You access a field within a variable by:
<delphi>
+
<syntaxhighlight>
 
  VariableIdentifier.FieldIdentifier
 
  VariableIdentifier.FieldIdentifier
</delphi>
+
</syntaxhighlight>
  
 
A period separates the variable and the field name.
 
A period separates the variable and the field name.
  
 
There's a very useful statement for dealing with records. If you are going to be using one record variable for a long time and don't feel like typing the variable name over and over, you can strip off the variable name and use only field identifiers. You do this by:
 
There's a very useful statement for dealing with records. If you are going to be using one record variable for a long time and don't feel like typing the variable name over and over, you can strip off the variable name and use only field identifiers. You do this by:
<delphi>
+
<syntaxhighlight>
 
WITH RecordVariable DO
 
WITH RecordVariable DO
 
BEGIN
 
BEGIN
 
   ...
 
   ...
 
END;
 
END;
</delphi>
+
</syntaxhighlight>
  
 
Example:
 
Example:
<delphi>
+
<syntaxhighlight>
 
with Info do
 
with Info do
 
begin
 
begin
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   ZIP := 90210;
 
   ZIP := 90210;
 
end;
 
end;
</delphi>
+
</syntaxhighlight>
  
 
{|style=color-backgroud="white" cellspacing="20"
 
{|style=color-backgroud="white" cellspacing="20"

Revision as of 14:54, 24 March 2012

5E - Records (author: Tao Yue, state: unchanged)

A record allows you to keep related data items in one structure. If you want information about a person, you may want to know name, age, city, state, and zip.

To declare a record, you'd use:

TYPE
  TypeName = record
    identifierlist1 : datatype1;
    ...
    identifierlistn : datatypen;
  end;

For example:

type
  InfoType = record
    Name : string;
    Age : integer;
    City, State : String;
    Zip : integer;
  end;

Each of the identifiers Name, Age, City, State, and Zip are referred to as fields. You access a field within a variable by:

 VariableIdentifier.FieldIdentifier

A period separates the variable and the field name.

There's a very useful statement for dealing with records. If you are going to be using one record variable for a long time and don't feel like typing the variable name over and over, you can strip off the variable name and use only field identifiers. You do this by:

WITH RecordVariable DO
BEGIN
  ...
END;

Example:

with Info do
begin
  Age := 18;
  ZIP := 90210;
end;
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