Pascal allows the use of enumerated types as index types. For example, if we def
ID: 3838886 • Letter: P
Question
Pascal allows the use of enumerated types as index types. For example, if we define the enumerated type GreatLakes to have the values Erie, Ontario, Huron, Michigan, and Superior (ordered here by increasing volume of water), then we can define:
type GreatLakes = (Erie, Ontario, Huron, Michigan, Superior);
area: array [ GreatLakes ] of integer,
elevation: array [ GreatLakes ] of real;
(and give them values)
area := ( 9910, 7340, 23000, 22300, 31700 );
elevation := ( 570.38, 244.77, 578.68, 578.68, 600.38 );
Now we can access individual elements to find, for example, that
area[Erie] = 9910
area[Superior] = 31700
elevation[Huron] = elevation[Michigan] = 576.68
In the above definitions we stored the areas and elevations of the Great Lakes in vectors (1- dimensional arrays).
Restate these definitions in order to store the same information in a structure that is:
(a) A vector of records
For defining records, use the syntax:
Person: record
age: integer;
sex: (Male, Female);
height, weight: real;
married: Boolean;
end;
(b) A record of vectors
(c) A 2-dimensional array indexed by type GreatLakes and by another enumerated type.
Explanation / Answer
a.
type GreatLakes = (Erie, Ontario, Huron, Michigan, Superior);
TGreatLakes : record
Area : integer
Elevation : real
end;
TLakes: array [GreatLakes] of TGreatLakes
TLakes:= ( (9910, 570.38), (7340, 244.77), (23000, , 578.68), (22300, , 578.68), (31700, , 600.38 ) );
b.
TGreatLakes : record
type GreatLakes = (Erie, Ontario, Huron, Michigan, Superior);
area: array [ GreatLakes ] of integer,
elevation: array [ GreatLakes ] of real;
area := ( 9910, 7340, 23000, 22300, 31700 );
elevation := ( 570.38, 244.77, 578.68, 578.68, 600.38 );
end;
c.
type GreatLakes = (Erie, Ontario, Huron, Michigan, Superior);
TGreatLakes : array[GreatLakes,0..1] of real;
TGreatLakes:= ( (9910, 570.38), (7340, 244.77), (23000, , 578.68), (22300, , 578.68), (31700, , 600.38 ) );