Arrays
CSCE Multi-Dimensional 110
From James Tams material
J. Michael Moore
When To Use Arrays Of Different _______________
Determined by the data the number ____________________
___________ determines the number ______________ to use.
Examples:
(1D array)
Tracking grades for a class
Each cell contains the grade for a student i.e., grades[i]
There is _________________ that specifies which students
grades are being accessed
One dimension (which student)
(2D array)
Expanded grades program
Again there is ____________ that specifies which students
grades are being accessed
The __________________ can be used to specify which lab
assignment
J. Michael Moore
When To Use Arrays Of Different Dimensions
(2D array continued)
Student
Lab
grade
First
Second
Third
student
student
student
Lab1
Lab2
Lab3
Lab4
Lab5
:
LabN
J. Michael Moore
When To Use Arrays Of Different Dimensions
(2D array continued)
A _________ is an
Notice that each row is merely a _________ array containing
rows of _________
Columns
[1]
[2]
[3]
[4]
[1]
[2]
[3]
Rows
[4]
[5]
J. Michael Moore
When To Use Arrays Of Different Dimensions
(3D array take the ________ but allow for multiple ______).
The _______________________ specifies which section grades
are being tracked.
Section (Z)
Student (X = column)
Note:
Lab
Assignment
(Y = row)
1.The standard approach for specifying the dimensions is to
specify the row coordinate (Y) and then the column
coordinate (X).
2.The size of a _________ must be the same for all elements
along that _______ e.g., all ____ must be of the same ____
J. Michael Moore
When To Use Arrays Of Different Dimensions
Section 503
Section 502
Section 501
Student 1 Student 2 Student 3
Lab1
Lab2
Lab3
Lab4
Lab5
Lab6
Lab7
J. Michael Moore
Declaring Multi-Dimensional Arrays
Format:
(Two dimensional arrays)
Name : array [min..max, min..max] of type;
_____
_______
(Three dimensional arrays)
Name : array [min..max, min..max, min..max] of type;
Examples:
var johnFinances : array [1..3, 1..7] of real;
var cube
: array [1..6, 1..6, 1..6] of char;
J. Michael Moore
Declaring Multi-Dimensional Arrays As A Type
Format:
Type declaration
Type
name = array [min..max, min..max] of element type;
name = array [min..max, min..max, min..max]
of element type;
Variable declaration
array name : Type name;
J. Michael Moore
Declaring Multi-Dimensional Arrays As A Type
Example:
Type declaration
Finances = array [1..3, 1..7] of real;
Cube = array 1..6, [1..6, 1..6] of char;
Variable declaration
var johnFinances : Finances;
var aCube
: Cube;
J. Michael Moore
Accessing / Assigning Values To Elements
Format:
name [row][column] :=
value;
Example:
finances [1][1] := 4500;
writeln (finances[1][1]);
OR
finances [1, 1] := 4500;
writeln (finances[1, 1]);
J. Michael Moore
Multi-Dimensional Arrays And Input/Output
Arrays of ___________________ (including multi-dimensional
_________________ arrays) cannot be passed as parameters to:
read, readln, write, writeln.
Only ______________________ can be passed as parameters to
these procedures.
J. Michael Moore
A Character-Based Grid
program gridExample (input, output);
const
MAX_ROWS
= 4;
MAX_COLUMNS
= 4;
NUM_COMBINATIONS = 10;
type
Grid = array[1..MAX_ROWS, 1..MAX_COLUMNS] of char;
J. Michael Moore
A Character-Based Grid (2)
function generateElement (temp : integer) : char;
var
anElement : char;
begin
case (temp) of
1, 2, 3, 4, 5, 6 :
anElement := ' ';
7, 8, 9:
anElement := '*';
10:
anElement := '.';
J. Michael Moore
A Character-Based Grid (3)
else {still in case statement}
begin
writeln('<< Error with the random # generator.>>');
writeln('<< Value should be 1-',NUM_COMBINATIONS,
' but random value is ', temp);
anElement := '!';
end;
end;
generateElement := anElement;
end;
J. Michael Moore
A Character-Based Grid
procedure initialize (var aGrid : Grid);
var
r
: integer;
c
: integer;
temp : integer;
begin
for r := 1 to MAX_ROWS do
begin
for c := 1 to MAX_COLUMNS do
begin
temp := random(NUM_COMBINATIONS) + 1;
aGrid[r][c] := generateElement(temp);
end;
end;
end;
J. Michael Moore
A Character-Based Grid (5)
procedure display (aGrid : Grid);
var
row: integer;
column: integer;
begin
for row := 1 to MAX_ROWS do
begin
for column := 1 to MAX_COLUMNS do
begin
write(aGrid[row][column]);
end;
writeln;
end;
end;
J. Michael Moore
A Character-Based Grid (6)
procedure displayLines (aGrid : Grid);
var
row : integer;
column : integer;
begin
for row := 1 to MAX_ROWS do
begin
writeln(' - - - -');
for column := 1 to MAX_COLUMNS do
begin
write('|', aGrid[row][column]);
end;
writeln('|');
end;
writeln(' - - - -');
end;
J. Michael Moore
A Character-Based Grid (7)
begin
var aGrid : Grid;
initialize(aGrid);
writeln('Displaying grid');
writeln('===============');
display(aGrid);
writeln;
writeln('Displaying grid with bounding lines');
writeln('==========================');
displayLines(aGrid);
end.
J. Michael Moore