For Tuesday Read Gaddis, chapter 5, sections 6-9 Program 4 Any - - PowerPoint PPT Presentation

For Tuesday

• Read Gaddis, chapter 5, sections 6-9

Program 4

• Any questions?

• Write a method to determine the purchaser‟s

discount based on a code.

–If the code is 1, there is no discount. –If the code is 3, the discount is 15%. –If the code is 7, the discount is 10%. –If the code is 8, the discount is 30%. –If the code is 12, the discount is 4%.

• The method should return the discount. Use

a switch statement.

• A program is required to read a customer‟s name,

a purchase amount and a tax code. The tax code has the following meaning: „A‟ or „a‟ tax exempt (0%) „B‟ or „b‟ state sales tax only (3%) „C‟ or „c‟ federal and state sales tax (5%) „H‟ or „h‟ special sales tax (7%) The program must then compute the sales tax and the total amount due and print the customer‟s name, purchase amount, sales tax and total amount

• due. If the tax code is invalid, the program should

print an error message and set the purchase amount to zero.

Switches in Pseudocode

• Typically, just write the nested if.

Formatting Numbers

Random class

• A useful utility class.
• We may use it at some point during the

semester.

Increment and Decrement

Repetition

while loops

• while (condition)

statement

Problem 1

• Write a program that sums a sequence of
• integers. Assume that the first integer read

specifies the number of values remaining to be

• entered. Your program should read only one

value at a time. A typical input sequence might be 5 100 200 300 400 500

Loops in Pseudocode

Infinite Loops

Counting Loop

• Write a method to add the numbers 1 to 10 and

return the sum using a while loop.

Counting Loop 2

• Write a while loop to compute the sum of all

integers between first and second (including first and second), where first and second are integers and first <= second. You may not change the value of either first or second.

Sentinel Values

Using a sentinel

• Design and write a program that will prompt

for, receive, and total a collection of payroll amounts entered by the user until a sentinel amount of -99 is entered. After the sentinel has been entered, display the total payroll amount on the screen.

Loop and a Half

Designing a while Loop

• Determine what steps need to be repeated
• Figure out the stopping condition
• Reverse that to get the condition for the loop
• Determine whether a partial loop needs to be

done before or after the loop itself

Sentinel Again

• Write a program that finds the smallest of

several integers. Assume that input will end when a sentinel value of –999 is read. Do not count –999 as one of the integers to consider.

Do While loops

• Always execute the body at least once.
• Occasionally useful.
• Seldom the “right” answer.

Validating User Input

For loops

• Short hand for counting loops
• Any for loop can be rewritten as a while loop

Do Over

• Write a method to compute and return the sum
• f 1 to 10 using a for loop.