An Introduction to Programming with C++ Fifth Edition Chapter 8 More on the Repetition Structure.
-
date post
15-Jan-2016 -
Category
Documents
-
view
228 -
download
0
Transcript of An Introduction to Programming with C++ Fifth Edition Chapter 8 More on the Repetition Structure.
An Introduction to Programming with C++
Fifth Edition
Chapter 8More on the Repetition Structure
An Introduction to Programming with C++, Fifth Edition 2
Objectives
• Include the posttest repetition structure in pseudocode
• Include the posttest repetition structure in a flowchart
• Code a posttest loop using the C++ do while statement
• Nest repetition structures
An Introduction to Programming with C++, Fifth Edition 3
Concept Lesson
• Posttest Loops
• Coding the Posttest Loop
• Nested Repetition Structures
An Introduction to Programming with C++, Fifth Edition 4
Posttest Loops
• Loops can be pretest or posttest
• Condition in a posttest loop is evaluated with each loop iteration– Evaluation occurs after instructions within loop are
processed• Also called bottom-driven loops
An Introduction to Programming with C++, Fifth Edition 5
Posttest Loops (continued)
An Introduction to Programming with C++, Fifth Edition 6
Flowcharting a Posttest Loop
• Flowcharts illustrate why loops are referred to as pretest and posttest loops– Repetition diamond appears at the top of a pretest
loop, but at the bottom of a posttest loop
Flowcharting a Posttest Loop (continued)
An Introduction to Programming with C++, Fifth Edition 7
An Introduction to Programming with C++, Fifth Edition 8
Flowcharting a Posttest Loop (continued)
An Introduction to Programming with C++, Fifth Edition 9
Flowcharting a Posttest Loop (continued)
An Introduction to Programming with C++, Fifth Edition 10
Coding the Posttest Loop
• Use the while statement or the for statement to code a pretest loop in C++
• Use the do while statement to code a posttest loop in C++– The loop condition must be a Boolean expression
• Can contain variables, constants, functions, and arithmetic/comparison/logical operators
An Introduction to Programming with C++, Fifth Edition 11
Coding the Posttest Loop (continued)
An Introduction to Programming with C++, Fifth Edition 12
Posttest Loop Example – O’Donnell Incorporated Program
• Problem description– In January of each year, O’Donnell Incorporated
pays a 10% bonus to each of its salespeople– Bonus based on amount of sales made by
salesperson during previous year– Payroll clerk wants a program that calculates and
displays each salesperson’s bonus amount
An Introduction to Programming with C++, Fifth Edition 13
Posttest Loop Example – O’Donnell Incorporated Program (continued)
An Introduction to Programming with C++, Fifth Edition 14
Posttest Loop Example – O’Donnell Incorporated Program
(continued)
An Introduction to Programming with C++, Fifth Edition 15
Nested Repetition Structures
• In a nested repetition structure, one loop (inner loop) is placed entirely within another loop (outer loop)
Nested Repetition Structures (continued)
An Introduction to Programming with C++, Fifth Edition 16
An Introduction to Programming with C++, Fifth Edition 17
Nested Loop Example – Max Beauty Supply Program
• Max Beauty Supply divides its sales territory into two regions: Region 1 and Region 2
• Sales manager wants a program to enter the sales amounts for both regions, one region at a time– Program should calculate the total amount sold in
the current region, and display that information
An Introduction to Programming with C++, Fifth Edition 18
Nested Loop Example – Max Beauty Supply Program (continued)
An Introduction to Programming with C++, Fifth Edition 19
Nested Loop Example – Max Beauty Supply Program (continued)
An Introduction to Programming with C++, Fifth Edition 20
Nested Loop Example – Max Beauty Supply Program (continued)
An Introduction to Programming with C++, Fifth Edition 21
Nested Loop Example – Max Beauty Supply Program (continued)
An Introduction to Programming with C++, Fifth Edition 22
Summary
• A repetition structure can be a pretest or posttest loop– In a pretest loop, the loop condition is evaluated before
the instructions in the loop body are processed• Instructions may never be processed
• Use while or for statements
– In a posttest loop, the loop condition is evaluated after the instructions in the loop body are processed
• Instructions are always processed at least once
• Use the do while statement
• You can nest repetition structures
An Introduction to Programming with C++, Fifth Edition 23
Application Lesson: Using a Nested Repetition Structure in a C++ Program• Lab 8.1: Stop and Analyze
• Lab 8.2– Create a program that displays one or more
multiplication tables for Mrs. Johnson students
• Lab 8.3– Modify program so it uses a posttest loop (instead of
a pretest loop) to display the multiplication tables
• Lab 8.4: Desk-Check Lab
• Lab 8.5: Debugging Lab