Chapter 15

Answers to Exam Preparation Exercises

3. Array contents:

(a) Ex_A

COL 1 2 3

ROW

1 1 2 3

2 2 4 6

3 3 6 9

4 4 8 12

(b) Ex_B

COL 1 2 3

ROW

1 2 0 1

2 0 1 2

3 1 2 0

4 ? ? ?

(c) Ex_C

COL 1 2

ROW

1 2 3

2 2 3

3 2 3

4 2 3

5 2 3

6 2 3

7 2 3

8 4 5

6. Array Definitions:

(a) Table with 5 rows and six columns, containing Booleans:

CONST

MaxRow = 5;

MaxCol = 6;

TYPE

RowIndex = 1..MaxRow;

ColIndex = 1..MaxCol;

TableType = ARRAY[RowIndex, ColIndex] OF Boolean;

VAR

Table:

TableType;

(b) Table indexed from -5 to 0 and 'A' to 'F', that contains Real values:

TYPE

RowIndex = -5..0;

ColIndex = 'A'..'F';

TableType = ARRAY[RowIndex, ColIndex] OF Real;

VAR

Table:

TableType;

(c) A Char table with rows indexed by uppercase letters and columns by lowercase letters:

TYPE

RowIndex = 'A'..'Z';

ColIndex = 'a'..'z';

TableType = ARRAY[RowIndex, ColIndex] OF Char;

VAR

Table: TableType

Answers to Programming Warm-Up Exercises

5. Several questions in exercises 5 and 6 ask for procedures that process specific rows or columns. The solutions given are for the general case with the specific row or column passed as a parameter.

(a) Procedure to determine which team sold the most tickets during the first week:

PROCEDURE Best_Team_For_Week(CONST Tickets: Sold_Type;

Which_Week: Week_Range;

VAR Which_Team: Team_Range);

VAR

Team: Team_Range;

BEGIN (* Best_Team_For_Week *)

Which_Team := 1;

FOR Team := 2 TO Number_Of_Teams DO

IF Tickets[Team, Which_Week] >

Tickets[Which_Team, Which_Week]

THEN Which_Team := Team

END; (* Best_Team_For_Week *)

(b) Procedure to determine if a certain team sold the most tickets for any week:

FUNCTION Did_WhichTeam_Win (CONST Tickets: Sold_Type;

Which_Team: Team_Range): Boolean;

VAR

Week: Week_Range;

Week_Best: Team_Range;

Answer_Found: Boolean;

BEGIN (* Did_WhichTeam_Win *)

Answer_Found := False;

Week := 1;

REPEAT

Best_Team_For_Week(Tickets, Week, Week_Best);

IF Week_Best = Which_Team

THEN Answer_Found := True

ELSE Week := Week + 1

UNTIL Answer_Found OR (Week = Number_Of_Weeks);

IF Answer_Found

THEN Did_WhichTeam_Win := True

ELSE Did_WhichTeam_Win := False

END; (* Did_WhichTeam_Win *)

(c) Procedures to determine the week in which the most tickets were sold:

PROCEDURE Best_Week (CONST Tickets: Sold_Type;

VAR Which_Week: Week_Range);

VAR

Week: Week_Range;

Best_Sum, Sum: Integer;

PROCEDURE Sum_Week (CONST Tickets: Sold_Type;

Which_Week: Integer;

VAR Sum: Integer);

VAR

Team: Team_Range;

BEGIN (* Sum_Week *)

Sum := 0;

FOR Team := 1 TO Number_Of_Teams DO

Sum := Sum + Tickets[Team, Which_Week]

END; (* Sum_Week *)

(**************************************************)

BEGIN (* Best_Week *)

Sum_Week(Tickets, 1, Best_Sum);

Which_Week := 1;

FOR Week := 2 TO Number_Of_Weeks DO

BEGIN

Sum_Week(Tickets, Week, Sum);

IF Sum > Best_Sum

THEN

BEGIN

Best_Sum := Sum;

Which_Week := Week

END

END

END; (* Best_Week *)

(d) Procedures to determine the team that sold the most tickets:

PROCEDURE Best_Team (CONST Tickets: Sold_Type;

VAR Which_Team: Integer);

VAR

Sum, Best_Sum: Integer;

Team: Team_Range;

PROCEDURE Sum_Team (CONST Tickets: Sold_Type;

Which_Team: Integer;

VAR Sum: Integer);

VAR

Week: Week_Range;

BEGIN (* Sum_Team *)

Sum := 0;

FOR Week := 1 TO Number_Of_Weeks DO

Sum := Sum + Tickets[Which_Team,, Week]

END; (* Sum_Team *)

(*****************************************************)

BEGIN (* Best_Team *)

Sum_Team(Tickets, 1, Best_Sum);

Which_Team := 1;

FOR Team := 2 TO Number_Of_Teams DO

BEGIN

Sum_Team(Tickets, Team, Sum);

IF Sum > Best_Sum

THEN

BEGIN

Best_Sum := Sum;

Which_Team := Team

END

END

END; (* Best_Team *)

6. Procedures for sports database.

(a) Determine which school spent the most money on football:

PROCEDURE Max_Cost_For_Sport (CONST Cost_Of_Sports: Money_Type;

Which_Sport: Sport_Index:

VAR Which_School:

School_Index);

VAR

School: School_Index;

BEGIN (* Max_Cost_For_Sport *)

Which_School := 1;

FOR School := 2 TO Number_Of_Schools DO

IF Cost_Of_Sports[Which_Sport, School] >

Cost_Of_Sports[Which_Sport, Which_School]

THEN Which_School := School

END; (* Max_Cost_For_Sport *)

(b) Which sport did the last school spend the most money on:

PROCEDURE Max_Cost_For_School (CONST Cost_Of_Sports: Money_Type;

Which_School: School_Index;

VAR Which_Sport: Sport_Type);

VAR

Sport: Sport_Type;

BEGIN (* Max_Cost_For_School *)

Which_Sport := Football;

FOR Sport := Basketball TO Volleyball DO

IF Cost_Of_Sports[Sport, Which_School] >

Cost_Of_Sports[Which_Sport, Which_School]

THEN Which_Sport := Sport

END; (* Max_Cost_For_School *)

(c) Which school has the most basketball players:

PROCEDURE Most_Kids_For_Sport (CONST Kids_In_Sports: Participant_Type;

Which_Sport: Sport_Type;

VAR Which_School: School_Index);

VAR

School: School_Index;

BEGIN (* Most_Kids_In_Sport *)

Which_School := 1;

FOR School := 2 TO Number_Of_Schools DO

IF Kids_In_Sports[School, Which_Sport] >

Kids_In_Sports[Which_School, Which_Sport]

THEN Which_School := School

END; (* Most_Kids_In_Sport *)

(d) For the third school, which sport had the most kids:

PROCEDURE Most_Kids_For_School (CONST Kids_In_Sports: Participant_Type;

Which_School: School_Index;

VAR Which_Sport: Sport_Type);

VAR

Sport: Sport_Type;

BEGIN (* Most_Kids_For_School *)

Which_Sport := Football;

FOR Sport := Basketball TO Volleyball DO

IF Kids_In_Sports[Which_School, Sport] >

Kids_In_Sports[Which_School, Which_Sport]

THEN Which_Sport := Sport

END; (* Most_Kids_For_School *)

(e) Total spent on volleyball for all schools:

PROCEDURE Sum_Cost_For_Sport (CONST Cost_Of_Sports: Money_Type;

Which_Sport: Sport_Type;

VAR Sum: Real);

VAR

School: School_Index;

BEGIN (* Sum_Cost_For_Sport *)

Sum := 0.0;

FOR School := 1 TO Number_Of_Schools DO

Sum := Sum + Cost_Of_Sports[Which_Sport, School]

END; (* Sum_Cost_For_Sport *)

(f) Total students playing all sports:

PROCEDURE Sum_Kids_For_School (CONST Kids_In_Sports: Participant_Type;

Which_School: School_Index;

VAR Sum: Integer);

VAR

Sport: Sport_Type;

BEGIN (* Sum_Kids_For_School *)

Sum := 0;

FOR Sport := Football TO Volleyball DO

Sum := Sum + Kids_In_Sports[Which_School, Sport]

END; (* Sum_Kids_For_School *)

PROCEDURE Total_Kids (CONST KidslnSports: Participant_Type;

VAR Total: Integer);

VAR

School: School_Index;

School_Total: Integer;

BEGIN (* Total_Kids *)

Total := 0;

FOR School := 1 TO Number_Of_Schools DO

BEGIN

Sum_Kids_For_School(Kids_In_Sports, School,

School_Total);

Total := Total + School_Total

END

END; (* Total_Kids *)

(g) Which school had the most kids in sports:

PROCEDURE School_With_Most_Kids (CONST Kids_In_Sports:

Participant_Type;

VAR Which_School:

School_Index);

VAR

School: School_Index;

Max_Sum, Sum: Integer;

BEGIN (* School_With_Most_Kids *)

Which_School := 1;

Sum_Kids_For_School(Kids_In_Sports, 1, Max_Sum);

FOR School := 2 TO Number_Of_Schools DO

BEGIN

Sum_Kids_For_School(Kids_In_Sports, School, Sum);

IF Sum > Max_Sum

THEN

BEGIN

Max_Sum := Sum;

Which_School := School

END

END

END; (* School_With_Most_Kids *)

(h) On which sport was the most money spent:

PROCEDURE Sport_With_Most_Spent (CONST Cost_Of_Sports: Money_Type;

VAR Which_Sport: Sport_Type);

VAR

Sport: Sport_Type;

Sum, Max_Sum: Real;

BEGIN (* Sport_With_Most_Spent *)

Which_Sport := Football;

Sum_Cost_For_Sport(Cost_Of_Sports, Football, Max_Sum);

FOR Sport := Basketball TO Volleyball DO

BEGIN

Sum_Cost_For_Sport(Cost_Of_Sports, Sport, Sum);

IF Sum > Max_Sum

THEN

BEGIN

Max_Sum := Sum;

Which_Sport := Sport

END

END

END; (* Sport_With_Most_Spent *)

(i) Which sport had the most participants:

PROCEDURE Sum_Kids_For_Sport (CONST Kids_In_Sports:

Participant_Type;

Which_Sport: Sport_Type;

VAR Sum: Integer);

VAR

School: School_Index;

BEGIN (* Sum_Kids_For_Sport *)

Sum := 0;

FOR School := 1 TO Number_Of_Schools DO

Sum := Sum + Kids_In_Sports[School, Which_Sport]

END; (* Sum_Kids_For_Sport *)

PROCEDURE Sport_With_Most_Kids (CONST Kids_In_Sports:

Money_Type;

VAR Which_Sport: Sport_Type);

VAR

Sport: Sport_Type;

Sum, Max_Sum: Integer;

BEGIN (* Sport_With_Most_Kids *)

Which_Sport := Football;

Sum_Kids_For_Sport(Kids_In_Sports, Football, Max_Sum);

FOR Sport := Basketball TO Volleyball DO

BEGIN

Sum_Kids_For_Sport(Kids_In_Sports, Sport, Sum);

IF Sum > Max_Sum

THEN

BEGIN

Max_Sum := Sum;

Which_Sport := Sport

END

END

END; (* Sport_With_Most_Kids *)

9. Function to sum a given row in a table.

FUNCTION Sum_Row_I (Table: Table_Type;

Which_Row, Col_Limit: Integer): Integer;

VAR

Col, Sum: Integer;

BEGIN (* Sum_Row_I *)

Sum := 0;

FOR Col := 1 TO Table.Number_Columns DO

Sum := Sum + Table.Data[Which_Row, Col];

Sum_Row_I := Sum

END; (* Sum_Row_I *)