Lab 7 Student

Lab 7: Repetition Structures I
This lab accompanies Chapter 5 (pp. 163-183 and pp. 196-201) of Starting Out with Programming Logic & Design.

Name: ___________________________

Lab 7.1 –Condition Controlled with While and Do-While Loops: Pseudocode

Critical Review

A repetition structure causes a statement or set of statements to execute repeatedly.

Repetition structures are used to perform the same task over and over.

Repetition structures are commonly called loops

A condition-controlled loop uses a true/false condition to control the number of times that it repeats.

The general structure of a While loop with a condition-controlled statement is:

//Declare loop control variable
While condition Statement Statement Etc. //Ask Question that changes the loop control variable
End While

The general structure of a Do While loop with a condition-controlled statement is:

//Declare loop control variable
Do
Statement Statement Etc. //Ask Question that changes the loop control variable
While Condition

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Step 1: Examine the following pseudocode main module from Lab 4.1. Loops are commonly used to call modules multiple times. The best design is to use a loop around the module calls in Main.

Module main () //Declare local variables
Declare String clientName = “ “
Declare Real feetUTP = 0
Declare Real subTotal = 0
Declare Real taxCost = 0
Declare Real totalCost = 0

//Module calls
Call inputData(feetUTP, clientName)
Call calcCosts(feetUTP, subTotal, taxCost, totalCost)
Call displayBill(clientName, totalCost)

End Module

Step 2: In the space provided, re-write the pseudocode for the main module with a condition controlled While or a Do-While loop so that the program runs multiple times. Create a loop control variable named keepGoing of the data type string and initialize this variable to “y”. Don’t forget to indent the contents of your loop. (Reference: Modularizing the Code in the Body of a Loop, page 172).

Module main () Declare String keepGoing = y While keepGoing == y
Declare String clientName =
Declare Real feetUTP = 0
Declare Real subTotal = 0
Declare Real taxCost = 0
Declare Real totalCost = 0

Call inputData (feetUTP, clientName)
Call calcCosts (feetUTP, subTotal, taxCost, totalCost)
Call displayBill (clientName, totalCost)
End While
End Module

Lab 7.2 –Condition Controlled with While and Do-While Loops: Flowcharts

Critical Review

In a while loop, the question is asked first. After the statements process, the control goes back above the condition.

In a do-while loop, the question is asked last. The statements always process at least one time.

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Step 1: Examine the following main module from Lab 4.2. Loops are commonly used to call modules multiple times. The best design is to use a loop around the module calls in Main (Reference: Modularizing the Code in the Body of a Loop, p. 173).

Step 2: Redesign the main module with a condition controlled While or a Do-While loop so that the program runs multiple times, based on the pseudocode from Lab 7-1.

PASTE FLOWCHART HERE

Lab 7.3 –Count Controlled with While and Do-While Loops: Pseudocode

Critical Review

A count-controlled loop repeats a specific number of times.

The loop keeps a count of the number of times that it iterates, and when the count reaches a specified amount the loop stops.

A variable, known as a counter variable, is used to store the number of iterations that it has performed.

The three actions that take place are initialization, test, and increment.
Initialization: Before the loop begins, the counter variable is initialized to a starting value.
Test: The loop tests the counter variable by comparing it to a maximum value.
Increment: To increment a variable means to increase its value. This is done by adding one to the loop control variable.

Any loop can be used with a count-controlled loop.

The general structure of a While loop (although it is the same process with a Do-While loop) with a count-controlled statement is:

//Declare loop control variable
Declare Integer counter = 1
While condition Statement Statement Etc. //increment counter Set counter = counter + 1
End While

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Step 1: Understanding how to raise a number to the power of 2 is very important to the field of networking as it relates to binary conversion. Convert the following algorithm to pseudocode using a count controlled do while or while loop:

1. Create three integer variables called toPower, number, and counter. Set counter to 0, and toPower and number to 2.
2. Write a do while loop or while loop that will run 7 iterations.
3. Inside the loop, set toPower equal to 2 to the power of the number variable.
4. Display “2 to the power of”, number, “ is”, toPower to the screen
5. Increment counter and number by 1

Module Main()
Declare integer toPower = 2
Declare integer number = 2
Declare integer counter = 0
While Counter < <7
Set toPower = 2^Number
Display 2 to the power of, number, is,toPower, Counter += 1
Number += 1
End While
End Module

Lab 7.4 –Count Controlled with While and Do-While Loops: Flowcharts

Critical Review

In a count controlled while or do-while loop, the flowchart is essentially the same as a condition controlled, except you must create a counter and manually increment the counter variable. The general flow using a while loop looks as follows:

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Step 1: Using your pseudocode from lab 7-3, design either a while or a do while loop of raising 2 to the power of 2-8 to the screen.

PASTE FLOWCHART HERE
Lab 7.5 –While and Do While Loops: Visual Basic Challenge I

Critical Review

Visual Basic supports both While and Do While loops. The general syntax for a condition controlled loop is as follows:

While loop:

While keepGoing = "yes"

End While

Do While loop:

Do While keepGoing = "yes" Loop

Visual Basic will automatically end your While with an End While, and end your Do While with the Loop.

Count controlled loops are structured the same way, but you must declare a counter variable as an Integer as loops only count in whole increments. Additionally, do not forget to increment or decrement your counter variable.

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Write either the Pseudocode OR Flowchart AND the Visual Basic Code

Design a program that will use your pingMe() module from Lab 4-4. There should be a condition controlled loop in Main to run the program multiple times if the user wants. Additionally, in the pingMe() module, there should be a count controlled loop that will ping your system after a count down of 5 (Reference p. 199, Decrementing). You may use while or do while loops. Your output may look as follows:

PASTE FLOWCHART OR PSEUDOCODE HERE

PASTE VISUAL BASIC CODE HERE
Lab 7.6 –While and Do While Loops: Visual Basic Challenge II

Based on Lab 7-3 and 7-4, code the flowchart/pseudocode by converting 2 to the power of a number from 2 to 8. You should have a main module that calls a module called displayPower() as many times as the user types yes (using a condition controlled loop). The displayPower() module should use a count controlled loop that raises the toPower variable to 2 to the power of the number, such as toPower = 2 ^ number. The output should look as:

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PASTE VISUAL BASIC CODE HERE