A count-controlled loop iterates a specific number of times. Although you can write this with a While or a Do-While loop as performed in Lab 5, most programming languages provide a loop known as the For loop. This loop is specifically designed as a count-controlled loop.

The process of the For loop is:

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 count-controlled loop uses a variable known as a counter variable to store the number of iterations that it has performed.

Using the counter, the following three actions take place (Initialization, Test, and Increment).

The pseudocode for a for statement looks as follows:

For counterVariable = startingValue to maxValue

Statement

Statement

Statement

Etc.

End For

This lab requires you to implement a count-controlled loop using a For statement.

Step 1: Examine the following code.

Constant Integer MAX_HOURS = 24

Declare Integer hours

For hours = 1 to MAX_HOURS

Display "The hour is ", hours

End For

Step 2: Explain what you think will be displayed to the screen in Step 1. (Reference: For Statement, page 239):

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Step 3: Write a For loop that will print 60 minutes to the screen. Complete the missing lines of code.

Constant Integer MAX_MINUTES = ______________________

Declare Integer minutes

For _____________ = 1 to ___________________

Display ________________________________________

End For

Step 4: Write a For loop that will print 60 seconds to the screen. Complete the missing lines of code.

Constant Integer MAX_SECONDS = ______________________

Declare Integer seconds

For _____________ = 1 to ___________________

Display ________________________________________

End For

Step 5: For loops can also be used to increment by more than one. Examine the following code.

Constant Integer MAX_VALUE = 10

Declare Integer counter

For counter = 0 to MAX_VALUE Step 2

Display "The number is ", counter

End For

Step 6: Explain what you think will be displayed to the screen in Step 5. (Reference: Incrementing by Values Other than 1, page 244):

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Step 7: Write a For loop that will display the numbers starting at 20, then 40, then 60, and continuing the sequence all the way to 200.

Constant Integer MAX_VALUE = _________________

Declare Integer counter

For counter = ____________ to MAX_VALUE Step ____________

Display "The number is ", _____________________

End For

Step 8: For loops can also be used when the user controls the number of iterations. Examine the following code:

Declare Integer numStudents

Declare Integer counter

Display "Enter the number of students in class"

Input numStudents

For counter = 1 to numStudents

Display "Student #", counter

End For

Step 9: Explain what you think will be displayed to the screen in Step 8. (Reference: Letting the User Control the Number of Iterations, page 248):

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Step 10: For loops are also commonly used to calculate a running total. Examine the following code.

Declare Integer counter

Declare Integer total = 0

Declare Integer number

For counter = 1 to 5

Display "Enter a number: "

Input number

Set total = total + number

End For

Display "The total is: ", total

Step 11: Explain what you think will be displayed to the screen in Step 10. (Reference: Calculating a Running Total, page 255):

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Step 12: Write the missing lines for a program that will allow the user to enter how many ages they want to enter and then find the average.

Declare Integer counter

Declare Integer totalAge = 0

Declare Real averageAge = 0

Declare Integer age

Declare Integer number

Display "How many ages do you want to enter: "

Input ___________________________

For counter = 1 to number

Display "Enter age: "

Input ___________________

Set totalAge = _________________ + ________________

End For

averageAge = ___________________ / ___________________

Display "The average age is ", _______________________