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Tutorial 9

More on the Selection Structure

Overview

In Tutorial 8 the selection structure was introduced and implemented using the if and if/else forms of the structure. This tutorial continues discussing the selection structure by introducing and implementing the third form of the selection structure, which is the switch form. The concept of nesting selection structures is also discussed and implemented.

Objectives

After completing the tutorial, the student will be able to:

Lecture Notes

Review the selection structure and design methods

The selection structure, also called the decision structure, is one of the three basic control structures used in programming. The other two are sequence, which has been covered previously, and the repetition structure, which will be covered in a later tutorial. The selection structure is used when you would like the program to make a decision, or comparison. Then, dependent upon the outcome of the decision, one of two paths will be chosen (the true path or the false path). Note that the decision within the selection structure will also result in either true or false, which is called a boolean result.

While the concept of a selection structure is quite simple, it is important to properly design the selection structure. Both flowcharts and pseudocode have been covered previously (review if necessary), however new flowchart symbols will be now be introduced. The diamond symbol represents a decision and is called the selection/repetition symbol. Each diamond has one flowline entering the symbol, and two flowlines leaving the symbol. The two flowlines leaving the symbol represent the true and false paths and should be marked accordingly. See page 268 for an example of a flowchart containing a selection structure.

Even though flowcharts are commonly used in representing selection structures, many programmers still wish to use pseudocode. You should always use whichever design method is most effective for you. Many programmers will use a combination of flowcharts and pseudocode. Different programming structures may lend themselves to being designed in either a flowchart or pseudocode. See page 267 for an example of a selection structure in pseudocode.

Note: Now that the switch form of the selection structure is being introduced, the design process utilizing pseudocode and/or flowcharts, while similar, will look different from a standard if/else form of the structure. The same flowchart symbol is used to represent the condition (diamond), however instead of one flowline coming out of the structure for the true path, many flowlines may now be coming out of the structure. See Figure 9-16 on page 314 for an example.

Nesting a selection structure

You can nest a selection structure within either the true path or false path of another selection structure. You would use a nested selection structure if more than one decision needs to be made before the appropriate action can be taken. The outer selection structure always represents the primary decision, while the nested (or inner) selection structure always represents the secondary decision.

While nesting a selection structure seems to be fairly straight forward, one must properly design the nested structure if they wish to be successful in implementing their desired logic. Also, it is imperative to properly code the structure. Following the proper indentation rules, as well as making the code readable, is a must in order for the code to execute successfully. Please review the example on page 301. The problem is presented in pseudocode and flowchart form, as well as implementing the actual C++ code. Another example of just C++ code is presented on pages 304-305. Both of these examples are very good ones to define your own rules for coding nested selection structures.

Recognizing common logic errors

Typically, logic errors commonly made when writing selection structures are a result of one of the following mistakes:

In Figure 9-8 on page 308 you will find two algorithms. The first algorithm properly solves the problem, while the second algorithm improperly solves the problem. While it may appear that the second algorithm properly solves the problem (it would display "3-week vacation" as would the first if the status were F and the years were greater than 5), there is still a problem due to the way it is coded. The second algorithm will display "2-week vacation" if the status is not F and/or the number of years is less than or equal to 5. The first algorithm will only display "2-week vacation" if the status if F and the number of years is less than or equal to 5. As you can see, a logical operator (second algorithm) cannot simply be substituted for a nested structure (first algorithm).

Another common error made when writing a selection structure that contains a nested selection structure is to reverse the primary and secondary decisions. Figure 9-10 on page 309 shows an example of this type of error. Unlike the selection structures in the correct algorithm, which determine the employment status before determining the number of years employed, the selection structures in the incorrect algorithm determine the number of years employed before determining the employment status. By reversing these two decisions, the problem is completely changed.

The third common error made when writing selection structures is to include an unnecessary nested selection structure. In most cases, a selection structure containing this error still will produce the correct results, however it does so less efficiently than selection structures properly designed. Figure 9-12 on page 311 shows this type of error. Unlike the correct algorithm, which contains two selection structures, the inefficient algorithm contains three selection structures. Follow the code and produce the same desk-check table as in Figure 9-13. You will see while the correct result is obtained, it is obtained is a less efficient manner.

Multiple-path selection using if/else

Some algorithms require selection structures that are capable of choosing from several alternatives. You can create such selection structures, commonly referred to as multiple-path structures, using either the if/else or switch form of the selection structure. Review the two sets of code in Figure 9-15 on page 313. Although you can write the if/else selection structure using either of the two methods, the second version provides a much more convenient way of writing this logic, and is more readable. The next section discusses the switch form of selection structures, which is the other way of creating a multiple-path structure.

Coding the switch selection structure

Remember from tutorial 8 that most programming languages offer three forms of the selection structure: if, if/else, and switch (also referred to as case). Since tutorial 8 covered the if and if/else forms of the selection structure, the switch form of the selection structure will be covered in this tutorial. While the same logic may be represented using the if/else or nested if/else form of the selection structure, it is often simpler and clearer (remember readability) to use the switch form, especially in situations in which the selection structure has many paths from which to choose. The syntax of the C++ switch statement is listed below:

switch (selectorExpression)

{

case value1: one or more statements

LEFTSQUAREcase value2: one or more statementsRIGHTSQUARE

LEFTSQUAREcase valueN: one or more statementsRIGHTSQUARE

LEFTSQUAREdefault: one or more statements processed when the selectorExpression does not match any of the valuesRIGHTSQUARE

}//end switch

You will notice above that the switch clause is composed of the keyword switch followed by a selectorExpression enclose in parentheses. The selectorExpression can contain any combination of variables, constants, functions, and operators, as long as the combination results in a value whose data type is either bool, char, short, int, or long.

Between the switch statement’s opening and closing braces are the individual case clauses, each representing a different path that the selection structure can follow. You may have as many case clauses as necessary in a switch statement. If the switch statement includes a default clause, it is usually the last clause in the statement just before the ending brace.

Each of the individual clauses within the switch statement (except for the default clause) contains a value, followed by a colon. The data type of the value should be compatible with the data type of the selectorExpression. (This is similar to an if statement when a variable is being compared to a single data value). Following the colon in each case clause are one or more statements that will be processed when the selectorExpression matches that case’s value. Notice that the statement(s) within the case clause are not entered as a statement block (are not enclosed in braces).

Once a match has been made between the selectorExpression and a case’s value, and the statement(s) that you wish to have processed have been executed, you would like the computer to advance to the next statement after the switch statement. To enable the computer to do this, you must code the break statement after the statement(s) you wish to process for each case clause. The break statement tells the computer to break out of the switch statement at this point, and proceed to the next statement following the switch statement. Note that any remaining case clauses will not be checked, which would not be necessary anyway since we have a match.

Note that the last optional clause in the switch statement is the default clause. The statement(s) in the default clause are executed if no matches occur between the selectorExpression and a case’s value. (This is similar to the else clause in an if/else statement). Notice that there is not a break coded after the statement(s) in a default clause. This is because the default clause is the last thing coded in the switch statement.

Just like the if and if/else statements, the switch statement should end with a comment after the ending brace. Remember that this is good programming practice that will help with readability and modifiability.

Discussion Topics/Additional Activities

Solutions to Questions

  1. c 180 8. d switch
  2. d 3000 9. a diamond
  3. b 200 10. b case ‘3’:
  4. b Paul 11. b Paul
  5. a Jerry 12. c Sue
  6. b Paul 13. a Jerry
  7. c Sue

 

Solutions to Concept Lesson Exercises

 

  1. if (quantity == 10)
  2. cout << "Equal" << endl;

    else if (quantity > 10)

    cout << "Over 10" << endl;

    else cout << "Not over 10" << endl;

    //end ifs

     

  3. cout << "Enter the code: ";
  4. cin >> code;

    cout << "Enter the sales: ";

    cin >> sales;

    if (code == 1 || code == 2)

    cout << sales * .12 << endl;

    else if (code == 3)

    cout << sales * .15 << endl;

    else if (code == 4)

    cout << sales * .20 << endl;

    else cout << "Error" << endl;

    //end ifs

  5. cout << "Enter the code: ";

cin >> code;

cout << "Enter the sales: ";

cin >> sales;

switch (code)

{

case 1: cout << sales * .02 << endl;

break;

case 2:

case 3:

case 4: cout << sales * .05 << endl;

break;

case 5: cout << sales * .1 << endl;

break;

case 6:

case 7: cout << sales * .15 << endl;

break;

default: cout << "Error" << endl;

} //end switch

  

4.

//T9ConE04.cpp - displays a message based on the number entered by the user

#include <iostream>

using namespace std;

int main()

{

//declare variable

int animal = 0;

//enter input

cout << "Enter a number: ";

cin >> animal;

//display output

if (animal == 1)

cout << "Dog" << endl;

else if (animal == 2)

cout << "Cat" << endl;

else cout << "Bird" << endl;

//end ifs

return 0;

} //end of main function

 

5.

//T9ConE05.cpp - displays the month corresponding to the number entered by the user

#include <iostream>

using namespace std;

int main()

{

//declare variable

int month = 0;

//enter input

cout << "Enter the month number: ";

cin >> month;

//display output

switch (month)

{

case 1: cout << "January" << endl;

break;

case 2: cout << "February" << endl;

break;

case 3: cout << "March" << endl;

break;

case 4: cout << "April" << endl;

break;

case 5: cout << "May" << endl;

break;

case 6: cout << "June" << endl;

break;

case 7: cout << "July" << endl;

break;

case 8: cout << "August" << endl;

break;

case 9: cout << "September" << endl;

break;

case 10: cout << "October" << endl;

break;

case 11: cout << "November" << endl;

break;

case 12: cout << "December" << endl;

break;

default: cout << "Error" << endl;

} //end switch

return 0;

} //end of main function

 

6.

//T9ConE06.cpp - displays a bonus amount

#include <iostream>

using namespace std;

int main()

{

//declare variables

int sales = 0;

int bonus = 0;

//enter input

cout << "Enter the sales amount: ";

cin >> sales;

//assign bonus

if (sales >= 100 && sales <= 250)

bonus = 25;

else if (sales > 250)

bonus = 50;

else bonus = 0;

//end ifs

//display output

cout << "Bonus: " << bonus << endl;

return 0;

} //end of main function

 

7.

//T9ConE07.cpp - displays a seminar fee

#include <iostream>

using namespace std;

int main()

{

//declare variables

char memberStatus = ' ';

int age = 0;

int fee = 0;

//enter status

cout << "Membership status (M for member and N for non-member): ";

cin >> memberStatus;

//assign seminar fee

if (memberStatus == 'M' || memberStatus == 'm')

{

cout << "Age: ";

cin >> age;

if (age < 65)

fee = 10;

else

fee = 5;

}

else

fee = 20;

//end ifs

//display output

cout << "Fee: " << fee << endl;

return 0;

} //end of main function

 

8.

//T9ConE08.cpp - displays a grade

#include <iostream>

using namespace std;

int main()

{

//declare variables

int score1 = 0;

int score2 = 0;

int score3 = 0;

float avg = 0.0;

char grade = ' ';

//enter scores

cout << "Score 1: ";

cin >> score1;

cout << "Score 2: ";

cin >> score2;

cout << "Score 3: ";

cin >> score3;

//calculate average

avg = (score1 + score2 + score3) / 3.0;

//assign grade

if (avg >= 90.0)

grade = 'A';

else if (avg >= 80.0)

grade = 'B';

else if (avg >= 70.0)

grade = 'C';

else if (avg >= 60.0)

grade = 'D';

else grade = 'F';

//end ifs

//display output

cout << "Grade: " << grade << endl;

return 0;

} //end of main function

 

9.

//T9ConE09.cpp - displays class rank

#include <iostream>

using namespace std;

int main()

{

//declare variable

int code = 0;

//enter input

cout << "Enter the code: ";

cin >> code;

//display output

switch (code)

{

case 1: cout << "Freshman" << endl;

break;

case 2: cout << "Sophomore" << endl;

break;

case 3: cout << "Junior" << endl;

break;

case 4: cout << "Senior" << endl;

break;

default: cout << "Error" << endl;

} //end switch

return 0;

} //end of main function

 

10. b. Below Average

c. The switch statement does not display anything on the screen.

d. Below Average

Incomplete

 11.

//T9ConE11.cpp - displays a message based on the day number entered by the user

#include <iostream>

using namespace std;

int main()

{

//declare variable

int day = 0;

//enter input

cout << "Enter the day (1 through 12): ";

cin >> day;

//display output

switch (day)

{

case 1: cout << "1 partridge in a pear tree" << endl;

break;

case 2: cout << "2 turtle doves" << endl;

break;

case 3: cout << "3 french hens" << endl;

break;

case 4: cout << "4 calling birds" << endl;

break;

case 5: cout << "5 golden rings" << endl;

break;

case 6: cout << "6 geese a laying" << endl;

break;

case 7: cout << "7 swans a swimming" << endl;

break;

case 8: cout << "8 maids a milking" << endl;

break;

case 9: cout << "9 ladies dancing" << endl;

break;

case 10: cout << "10 lords a leaping" << endl;

break;

case 11: cout << "11 pipers piping" << endl;

break;

case 12: cout << "12 drummers drumming" << endl;

break;

default: cout << "Error in day number." << endl;

} //end switch

return 0;

} //end of main function

 

 12.

//T9ConE12.cpp - displays the price of an order

#include <iostream>

using namespace std;

int main()

{

//declare variables

int status = 0;

int units = 0;

//enter input

cout << "Customer status (1 for wholesaler, 2 for retailer): ";

cin >> status;

cout << "Number of units ordered: ";

cin >> units;

//calculate and display order price

switch (status)

{

case 1: if (units >= 1 && units <= 4)

cout << "Total $" << units * 10 << endl;

else if (units >= 5)

cout << "Total $" << units * 9 << endl;

else cout << "Invalid number of units." << endl;

break;

case 2: if (units >= 1 && units <= 3)

cout << "Total $" << units * 15 << endl;

else if (units >= 4 && units <= 8)

cout << "Total $" << units * 14 << endl;

else if (units >= 9)

cout << "Total $" << units * 12 << endl;

else cout << "Invalid number of units." << endl;

break;

default: cout << "Invalid status." << endl;

} //end switch

return 0;

} //end of main function

 13. Changes made to the original code are shaded.

/T9ConE13.cpp - displays the state

//corresponding to the code entered by the user

#include <iostream>

using namespace std;

int main()

{

//declare variable

int stateCode = 0;

//enter input item

cout << "Enter a number from 1 to 5: ";

cin >> stateCode;

//display output

switch (stateCode)

{

case 1: cout << "Illinois" << endl;

break;

case 2: cout << "Kentucky" << endl;

break;

case 3: cout << "New Hampshire" << endl;

break;

case 4: cout << "Vermont" << endl;

break;

case 5: cout << "Massachusetts" << endl;

break;

default: cout << "Unknown state" << endl;

}

//end switch

return 0;

} //end of main function

 

Solutions to Application Lesson Exercises

 

1.

//T9AppE01.cpp - displays the commission

#include <iostream>

using namespace std;

//function prototype

float calcCommission(int);

int main()

{

int sales = 0;

float commission = 0.0;

//enter input data

cout << "Enter sales: ";

cin >> sales;

if (sales > 0)

{

//calculate and display commission

commission = calcCommission(sales);

cout << "Commission: " << commission << endl;

}

else

cout << "No commission calculated" << endl;

//end if

return 0;

} //end of main function

//*****program-defined functions*****

float calcCommission(int amountSold)

{

//calculates and returns the commission

float commDollars = 0.0;

if (amountSold <= 100000)

commDollars = amountSold * .02;

else if (amountSold <= 200000)

commDollars = amountSold * .04;

else if (amountSold <= 300000)

commDollars = amountSold * .06;

else if (amountSold <= 400000)

commDollars = amountSold * .08;

else commDollars = amountSold * .1;

//end ifs

return commDollars;

} //end of calcCommission function

 

2.

IPO charts:

main function

Input

Processing

Output

number of registrants

 

Processing items: none

Algorithm:

  1. enter the number of people registered
  2. if (the number of people registered > 0)

total owed = calcTotalOwed(number of registrants)

display the total owed

else

display "Incorrect number" message

total owed

calcTotalOwed function

Input

Processing

Output

number of registrants

 

 

Processing items:

fee per person

Algorithm:

  1. if (the number of registrants <= 4)
  2. assign 100 as the fee per person

    else if (the number of registrants <= 10)

    assign 80 as the fee per person

    else assign 60 as the fee per person

  3. calculate the total owed by multiplying the number of registrants by the fee per person
  4. return the total owed

total owed

 

Desk-check tables:

main function

registrants

totalOwed

0


4

0

8

0

12

0

0

0

-2

0

400

0

640

0

720

0

0

calcTotalOwed function

people

feePerPerson

total


4

8

12

0

100

0

80

0

60

0

400

0

640

0

720

  

 

//T9AppE02.cpp - displays the total owed

#include <iostream>

using namespace std;

//function prototype

int calcTotalOwed(int);

int main()

{

int registrants = 0;

int totalOwed = 0;

//enter input data

cout << "Enter number of registrants: ";

cin >> registrants;

if (registrants > 0)

{

//calculate and display total owed

totalOwed = calcTotalOwed(registrants);

cout << "Total owed: " << totalOwed << endl;

}

else

cout << "Incorrect number" << endl;

//end if

return 0;

} //end of main function

//*****program-defined functions*****

int calcTotalOwed(int people)

{

//calculates and returns the total owed

int feePerPerson = 0;

int total = 0;

if (people <= 4)

feePerPerson = 100;

else if (people <= 10)

feePerPerson = 80;

else

feePerPerson = 60;

//end ifs

total = people * feePerPerson;

return total;

} //end of calcTotalOwed function

 3.

IPO Chart:

Input

Processing

Output

state code

 

Processing items: none

Algorithm:

  1. enter the state code
  2. case of state code

1 display 25

2, 5, 6 display 30

3, 4 display 40

Other display "Incorrect state code"

shipping charge

 

Desk-check table:

stateCode

0


1

0

2

0

3

0

4

0

5

0

6

0

7

0

-2

  

//T9AppE03.cpp - displays a shipping charge

#include <iostream>

using namespace std;

int main()

{

int stateCode = 0;

//enter input data

cout << "Enter the state code: ";

cin >> stateCode;

//display shipping charge

switch (stateCode)

{

case 1: cout << "Shipping charge is $25" << endl;

break;

case 2:

case 5:

case 6: cout << "Shipping charge is $30" << endl;

break;

case 3:

case 4: cout << "Shipping charge is $40" << endl;

break;

default: cout << "Incorrect state code" << endl;

} //end switch

return 0;

} //end of main function

 4.

IPO Chart:

Input

Processing

Output

seat location

Processing items: none

Algorithm:

  1. enter the seat location
  2. if (the seat location is B or b)

display 75 as the price

else if (the seat location is P or p)

display 30 as the price

else if (the seat location is L or l)

display 21 as the price

else display an error message

end ifs

price

 

Desk-check table:

location


B


p


L


g

 

//T9AppE04.cpp - displays the price of a concert ticket

#include <iostream>

using namespace std;

int main()

{

char location = ' ';

//enter input data

cout << "Enter the seat location: ";

cin >> location;

//display ticket price

if (location == 'B' || location == 'b')

cout << "Ticket price: $75" << endl;

else if (location == 'P' || location == 'p')

cout << "Ticket price: $30" << endl;

else if (location == 'L' || location == 'l')

cout << "Ticket price: $21" << endl;

else cout << "Invalid location" << endl;

//end ifs

return 0;

} //end of main function

 5.

IPO Chart:

Input

Processing

Output

years employed

Processing items: none

Algorithm:

  1. enter the years employed
  2. if (the years employed is 0)

display 0 as the vacation weeks

else if (the years employed is less than or equal to 5)

display 1 as the vacation weeks

else if (the years employed is less than or equal to 10)

display 2 as the vacation weeks

else if (the years employed is greater than 10)

display 3 as the vacation weeks

else display "Invalid years" message

end ifs

vacation weeks

Desk-check table:

years

0

0

0

2

0

10

0

11

0

-2

//T9AppE05.cpp - displays the number of vacation weeks due an employee

#include <iostream>

using namespace std;

int main()

{

int years = 0;

//enter input data

cout << "Enter the years employed: ";

cin >> years;

//display vacation weeks

if (years == 0)

cout << "Vacation weeks: 0" << endl;

else if (years > 0 && years <= 5)

cout << "Vacation weeks: 1" << endl;

else if (years > 5 && years <= 10)

cout << "Vacation weeks: 2" << endl;

else if (years > 10)

cout << "Vacation weeks: 3" << endl;

else cout << "Invalid years" << endl;

//end ifs

return 0;

} //end of main function

6.

//T9AppE06.cpp - displays fat calories and fat percentage

#include <iostream>

using namespace std;

//function prototype

void calcFatInfo(int, int, int &, float &);

int main()

{

int totalCal = 0;

int fatGrams = 0;

int fatCal = 0;

float fatPercent = 0.0;

//enter input data

cout << "Total calories: ";

cin >> totalCal;

cout << "Grams of fat: ";

cin >> fatGrams;

//validate input data

if (totalCal >= 0 && fatGrams >= 0)

{

//valid data

calcFatInfo(totalCal, fatGrams, fatCal, fatPercent);

cout << fixed;

cout.precision(0);

cout << "Fat calories: " << fatCal << endl;

cout << "Fat percentage: " << fatPercent << "%" << endl;

if (fatPercent <= 30)

cout << "Low-fat food" << endl;

else

cout << "High-fat food" << endl;

//end if

}

else //invalid data

cout << "Input error" << endl;

//end if

return 0;

} //end of main function

//*****program-defined functions*****

void calcFatInfo(int tCal, int grams, int &fCal, float &fPer)

{

//calculate fat calories and fat percentage

fCal = grams * 9;

fPer = float(fCal) / float(tCal) * 100;

} //end of calcFatInfo function

 7.

IPO charts:

main function

Input

Processing

Output

gender

activity level

current weight

 

Processing items:

data OK

Algorithm:

  1. data OK = getInputData(gender, activity level, current weight)
  2. if (data OK is Y)

calculate daily calories = calcDailyInfo(gender, activity level, current weight)

display daily calories

else

display error message

daily calories

getInputData function

Input

Processing

Output

address of gender

address of activity level

address of current weight

 

Processing items: none

Algorithm:

  1. enter gender
  2. if (gender is F or f or M or m)
  3. get activity level

    if (activity level is A or a or I or I)

    get current weight

    assign Y to valid

  4. return valid

gender

activity level

current weight

valid (N)

calcDailyInfo function

Input

Processing

Output

gender

activity level

current weight

 

Processing items: none

Algorithm:

  1. if (gender is F or f)
  2. if (activity level is A or a)

    daily calories = current weight * 12

    else

    daily calories = current weight * 10

    else

    if (activity level is A or a)

    daily calories = current weight * 15

    else

    daily calories = current weight * 13

  3. return daily calories

daily calories

 Desk-check tables:

gender (main)

sex (getInputData)

activityLevel (main)

level (getInputData)

currentWeight (main)

pounds (getInputData)


F


F


M


M


G


F


I


A


I


A




B

0

150

0

120

0

180

0

200

0

0

main function only getInputData function only

dataOK

dailyCalories

 

validData


Y


Y


Y


Y


N


N

0

1500

0

1440

0

2340

0

3000

0

0

 

N

Y

N

Y

N

Y

N

Y

N

N

calcDailyInfo function only

femaleMale

activity

curWeight

maintainCals

F

F

M

M

I

A

I

A

150

120

180

200

0

1500

0

1440

0

2340

0

3000

  

 

//T9AppE07.cpp - displays the number of daily calories needed to maintain current weight

#include <iostream>

using namespace std;

//function prototypes

char getInputData(char &, char &, int &);

int calcDailyInfo(char, char, int);

int main()

{

char gender = ' ';

char activityLevel = ' ';

int currentWeight = 0;

char dataOk = ' ';

int dailyCalories = 0;

//enter input data

dataOk = getInputData(gender, activityLevel, currentWeight);

if (dataOk == 'Y')

{

//calculate calories

dailyCalories = calcDailyInfo(gender, activityLevel, currentWeight);

cout << "Daily calories " << dailyCalories << endl;

}

else

cout << "Incorrect input data entered" << endl;

//end if

return 0;

} //end of main function

//*****program-defined functions*****

char getInputData(char &sex, char &level, int &pounds)

{

char validData = 'N';

cout << "Gender (F for female or M for male): ";

cin >> sex;

if (sex == 'F' || sex == 'f' || sex == 'M' || sex == 'm')

{

cout << "Activity level (A for active or I for inactive): ";

cin >> level;

if (level == 'A' || level == 'a' || level == 'I' || level == 'i')

{

cout << "Current weight: ";

cin >> pounds;

validData = 'Y';

} //end if

} //endif

return validData;

} //end of getInputData function

 

int calcDailyInfo(char femaleMale, char activity, int curWeight)

{

int maintainCals = 0;

if (femaleMale == 'F' || femaleMale == 'f')

{

if (activity == 'A' || activity == 'a')

maintainCals = curWeight * 12;

else

maintainCals = curWeight * 10;

//end if

}

else //male

{

if (activity == 'A' || activity == 'a')

maintainCals = curWeight * 15;

else

maintainCals = curWeight * 13;

//end if

}//end if

return maintainCals;

} //end of calcDailyInfo function

 8.

IPO Chart:

Input

Processing

Output

score 1

score 2

 

Processing items:

average

Algorithm:

  1. get score 1
  2. if (score 1 is less than 0)

display error message

else

get score 2

if (score 2 is less than 0)

display error message

else

calculate the average by adding together score 1 and score 2, and then dividing the sum by 2

if (the average is greater than or equal to 70)

display "Pass" message

else

display "Fail" message

message (Pass or Fail)

 

Desk-check table:

test1

test2

avg

0.0

95.0

0.0

65.0

0.0

0.0

0.0

80.0

0.0

-1.0

0.0

73.0

0.0

50.0

0.0

100.0

0.0

-3.0

0.0

0.0

84.0

0.0

57.5

0.0

50.0

0.0

0.0

 

//T9AppE08.cpp - displays a message indicating

//whether a student passed or failed a course

#include <iostream>

using namespace std;

int main()

{

float test1 = 0.0;

float test2 = 0.0;

float avg = 0.0;

//enter input data

cout << "Enter first test score: ";

cin >> test1;

//display message

if (test1 < 0)

cout << "You entered a negative score for the first test." << endl;

else

{

cout << "Enter second test score: ";

cin >> test2;

if (test2 < 0)

cout << "You entered a negative score for the second test." << endl;

else

{

avg = (test1 + test2) / 2;

if (avg >= 70)

cout << "Pass" << endl;

else

cout << "Fail" << endl;

//end if

} //end if

} //end if

return 0;

} //end of main function

 9.

IPO Chart:

Input

Processing

Output

operation

num 1

num 2

 

Processing items:

temp

Algorithm:

  1. get operation
  2. if (operation is not A, a, S, or s)

display error message

else

get num 1

get num2

if (operation is A or a)

calculate sum by adding together num 1 and num 2

display sum

else

if (num 1 is less than num 2)

assign num 1 to temp

assign num 2 to num 1

assign temp to num 2

end if

calculate the difference by subtracting num 2 from num 1

display the difference

end if

end if

sum or difference

 

Desk-check table:

operation

num1

num2

sum

diff

temp


A


a


S


s


G

0

10

0

45

0

65

0

7

13

0

0

20

0

15

0

50

0

13

7

0

0

30

0

60

0

0

0

0

0

0

15

0

6

0

0

0

0

0

7

0

  

//T9AppE09.cpp - displays either the sum or difference

#include <iostream>

using namespace std;

int main()

{

char operation = ' ';

int num1 = 0;

int num2 = 0;

int sum = 0;

int diff = 0;

int temp = 0;

//enter input data

cout << "Enter operation (A or S): ";

cin >> operation;

//display message

if (operation != 'A' && operation != 'a' && operation != 'S' && operation != 's') cout << "Incorrect operation" << endl;

else

{

cout << "Enter first number: ";

cin >> num1;

cout << "Enter second number: ";

cin >> num2;

if (operation == 'A' || operation == 'a')

{

sum = num1 + num2;

cout << "Sum: " << sum << endl;

}

else

{

if (num1 < num2)

{

temp = num1;

num1 = num2;

num2 = temp;

} //end if

diff = num1 - num2;

cout << "Difference: " << diff << endl;

} //end if

} //end if

return 0;

} //end of main function

 10.

//T9AppE10.cpp - displays the commission

#include <iostream>

using namespace std;

//function prototypes

float calcCommission(int);

char getAndValidateSales(int &);

int main()

{

int sales = 0;

float commission = 0.0;

char validData = ' ';

//enter input data

validData = getAndValidateSales(sales);

if (validData == 'Y')

{

//calculate and display commission

commission = calcCommission(sales);

cout << "Commission: " << commission << endl;

}

else

cout << "No commission calculated" << endl;

//end if

return 0;

} //end of main function

//*****program-defined functions*****

char getAndValidateSales(int &dollars)

{

char valid = 'N';

cout << "Enter sales: ";

cin >> dollars;

if (dollars > 0)

valid = 'Y';

return valid;

} //end of getAndValidateSales function

float calcCommission(int amountSold)

{

//calculates and returns the commission

float commDollars = 0.0;

if (amountSold <= 100000)

commDollars = amountSold * .02;

else if (amountSold <= 400000)

commDollars = 2000 + .05 * (amountSold - 100000);

else commDollars = 17000 + .1 * (amountSold - 400000);

//end ifs

return commDollars;

} //end of calcCommission function

 11. Changes to the original code are shaded.

//T9AppE11.cpp - displays the salary amount

//corresponding to the code entered by the user

#include <iostream>

using namespace std;

int main()

{

//declare variable

int code = 0;

//get code from user

cout << "Enter the code (1 through 5): ";

cin >> code;

//display salary

 

if (code == 1)

cout << "$45,000" << endl;

else if (code == 2 || code == 5)

cout << "$33,000" << endl;

else if (code == 3 || code == 4)

cout << "$25,000" << endl;

else

cout << "Entry error" << endl;

 

//end ifs

return 0;

} //end of main function