Presentation on theme: "Chapter 2: Beginning the Problem-Solving Process"— Presentation transcript:
1 Chapter 2: Beginning the Problem-Solving Process
Introduction to Programming with C++ Fourth Edition
2 Objectives Explain the problem-solving process used to create a computer program Analyze a problem Complete an IPO chart Plan an
algorithm using pseudocode and flowcharts Desk-check an algorithm Introduction to Programming with C++, Fourth Edition
3 Problem Solving/Solving Everyday Problems
Steps include: Analysis Planning
Review Implementation Evaluation Modification Introduction to Programming with C++, Fourth Edition
4 Analysis and Planning Introduction to
Programming with C++, Fourth Edition
5 Modified Algorithm Introduction to Programming with C++, Fourth Edition
6 Creating Computer Solutions to Problems
Introduction to Programming with C++, Fourth Edition
7 Analyzing the Problem Purpose of analyzing the problem:
to determine the goal to determine the items needed to achieve the goal Introduction to Programming with C++, Fourth Edition
8 Analyzing the Problem (continued)
Introduction to Programming with C++, Fourth Edition
9
IPO (Input, Processing, Output) Charts
Used by programmers to organize and summarize the results of a problem analysis To determine input: Search the problem specification for an answer to the following question: What information will the computer need to know to print, display, or store the output items? Introduction to Programming with C++, Fourth Edition
10 IPO Chart with Input and Output
Introduction to Programming with C++, Fourth Edition
11 Determining
Important Information
If you are not sure if a piece of information is important, ask yourself this question: If I didn’t know this information, could I still solve the problem? When reading a problem specification, it helps to use a pencil to lightly cross out unnecessary information Introduction to Programming with C++, Fourth Edition
12 Problem Specification
Introduction to Programming with C++, Fourth Edition
13 Problem Specification
Lacking Information
Introduction to Programming with C++, Fourth Edition
14 Problem Specification with Input not Stated
Introduction to Programming with C++, Fourth Edition
15 Planning the Algorithm
Processing item - an intermediate value that the algorithm uses when processing the input into the output Pseudocode - a tool programmers use to help them plan an algorithm Flowchart - uses standardized symbols to show the steps the computer needs to take to accomplish the
program’s goal Introduction to Programming with C++, Fourth Edition
16 Completed IPO Chart Introduction to Programming with C++, Fourth Edition
17 IPO Chart with Flow Chart
Introduction to Programming with C++, Fourth Edition
18
Flowchart Symbols Flowlines - used to connect symbols
Start/stop symbol (oval) – indicates beginning of flowchart Process symbols (rectangles) – used to represent tasks such as calculations Input/output symbol (parallelogram) - used to represent input tasks Introduction to Programming with C++, Fourth Edition
19 Solving Sarah’s Problem
Introduction to Programming with C++, Fourth Edition
20 IPO Chart for Problem Specification
Introduction to Programming with C++, Fourth Edition
21 Hints for Planning Algorithms
Introduction to Programming with C++, Fourth Edition
22 Desk-Checking the
Algorithm
Reasons for desk-checking: To verify that the program is not missing any steps To verify that the existing steps are correct and in the proper order Introduction to Programming with C++, Fourth Edition
23 Desk-Check Table
with New Weekly Pay
Introduction to Programming with C++, Fourth Edition
24 Results of Second Desk-Check
Introduction to Programming with C++, Fourth Edition
25 The Gas Mileage Problem
Introduction to Programming with C++, Fourth Edition
26 The Gas Mileage Problem
(continued)
Analyze the problem looking for nouns and adjectives that represent both input and output Output should answer the following question: What does the user want to see printed on paper, displayed on the screen, or stored in a file? Input should answer the following question: What information will the computer need to know to print, display, or store the output items? Introduction to Programming with C++, Fourth Edition
27 IPO Chart Introduction to Programming with C++, Fourth Edition
28 Completed Desk-Check Table
Introduction to Programming with C++, Fourth Edition
29 Summary Explain
the problem-solving process used to create a computer program Complete an IPO chart Use algorithms (pseudocode) and flowcharts Use desk-checking techniques Introduction to Programming with C++, Fourth Edition