[PASCAL] Records

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Records

 

While arrays can hold many variables of the same type, records can hold variables of different types, and these variables are called 'Fields'.
This group of variables/fields can be treated as a single unit or variable. We can use records to store information that belong to the same object, for example, car information:

 

1. Car type: string variable
2. Engine size: real number
3. Production year: integer value
We can collect these different types in one record which represents a Car as in the following example:

 

program Cars;
{$mode objfpc}{$H+}
uses
 {$IFDEF UNIX}{$IFDEF UseCThreads}
 cthreads,
 {$ENDIF}{$ENDIF}
 Classes
 { you can add units after this };
type
 TCar = record
 ModelName: string;
 Engine: Single;
 ModelYear: Integer;
 end;
var
 Car: TCar;
begin
 Write('Input car Model Name: ');
 Readln(Car.ModelName);
 Write('Input car Engine size: ');
 Readln(Car.Engine);
 Write('Input car Model year: ');
 Readln(Car.ModelYear);
 Writeln;
 Writeln('Car information: ');
 Writeln('Model Name : ', Car.ModelName);
 Writeln('Engine size : ', Car.Engine);
 Writeln('Model Year : ', Car.ModelYear);
 Write('Press enter key to close..');
 Readln;
end.

 

In this example ,we have defined a new type (Record) using the 'type' keyword:

 

type
 TCar = record
 ModelName: string;
 Engine: Single;
 ModelYear: Integer;
 end;

 

We have added the letter (T) to Car to indicate that this is a type and not a variable. Variable names could be like: Car, Hour, UserName, but type names should be like: TCar, THouse, and TUserName. This is a standard in the Pascal language.

 

When we need to use this new type, then we should declare a variable of that type, for example:

 

var
 Car: TCar;

 

If we need to store a value in one of its variables/fields, we should access it like this:

 

 Car.ModelName

 

Edited November 12, 2020 by CouldnoT

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Topic closed.