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An Introduction to Programming with C++ Fifth Edition

An Introduction to Programming with C++ Fifth Edition. Chapter 2 Beginning the Problem-Solving Process. 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

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An Introduction to Programming with C++ Fifth Edition

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  1. An Introduction to Programming with C++Fifth Edition Chapter 2 Beginning the Problem-Solving Process

  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 An Introduction to Programming with C++, Fifth Edition

  3. Concept Lesson • Problem Solving • Solving Everyday Problems • Creating Computer Solutions to Problems • Analyzing the Problem • Planning the Algorithm • Desk-Checking the Algorithm • The Gas Mileage Problem • Summary An Introduction to Programming with C++, Fifth Edition

  4. Problem Solving • In this lesson, you will: • Explore the thought process followed when solving problems • Learn how to use a similar process to create a computer solution to a problem • Called a computer program An Introduction to Programming with C++, Fifth Edition

  5. Solving Everyday Problems • First step in solving a problem: analyze it • E.g., problem of being hungry • Next, you plan, review, implement, evaluate, and modify (if necessary) the solution • E.g., if you are still hungry An Introduction to Programming with C++, Fifth Edition

  6. Solving Everyday Problems (continued) An Introduction to Programming with C++, Fifth Edition

  7. Solving Everyday Problems (continued) An Introduction to Programming with C++, Fifth Edition

  8. Creating Computer Solutions to Problems • Analysis tools: IPO charts, pseudocode, flowcharts • To desk-check or hand-trace,use pencil, paper, and sample data to walk through algorithm • A coded algorithm is called a program An Introduction to Programming with C++, Fifth Edition

  9. Creating Computer Solutions to Problems (continued) An Introduction to Programming with C++, Fifth Edition

  10. Analyzing the Problem • Analyze a problem to: • Determine the goal of solving it • Output • Determine the items needed to achieve that goal • Input • Always search first for the output An Introduction to Programming with C++, Fifth Edition

  11. Analyzing the Problem (continued) An Introduction to Programming with C++, Fifth Edition

  12. IPO Charts • Use an IPO chart to organize and summarize the results of a problem analysis • IPO:Input, Processing, and Output An Introduction to Programming with C++, Fifth Edition

  13. IPO Charts (continued) An Introduction to Programming with C++, Fifth Edition

  14. IPO Charts (continued) An Introduction to Programming with C++, Fifth Edition

  15. Analyzing the Problem (continued) • First, reduce the amount of information you need to consider in your analysis: An Introduction to Programming with C++, Fifth Edition

  16. Analyzing the Problem (continued) • Worse than having too much information is not having enough information to solve problem: An Introduction to Programming with C++, Fifth Edition

  17. Analyzing the Problem (continued) • Distinguish between information that is missing and information that is implied: An Introduction to Programming with C++, Fifth Edition

  18. Planning the Algorithm • Algorithm: set of instructions that will transform the problem’s input into its output • Record it in the Processing column of the IPO chart • Processing item: intermediate value used by algorithm when processing input into output • Pseudocode is a tool programmers use to help them plan an algorithm • Short English statements An Introduction to Programming with C++, Fifth Edition

  19. Planning the Algorithm (continued) An Introduction to Programming with C++, Fifth Edition

  20. Planning the Algorithm (continued) • Flowcharts are also used to plan an algorithm • Use standardized symbols • Symbols connected with flowlines • Oval: start/stop symbol • Rectangle: process symbol • Represents tasks such as calculations • Parallelogram: input/output symbol • Represents I/O tasks An Introduction to Programming with C++, Fifth Edition

  21. Planning the Algorithm (continued) An Introduction to Programming with C++, Fifth Edition

  22. Planning the Algorithm (continued) • A problem can have more than one solution: An Introduction to Programming with C++, Fifth Edition

  23. Hints for Writing Algorithms This problem specification is almost identical to the one shown earlier in Figure 2-4 An Introduction to Programming with C++, Fifth Edition

  24. Hints for Writing Algorithms (continued) You may use a portion of a previous solution to solve current problem An Introduction to Programming with C++, Fifth Edition

  25. Desk-Checking the Algorithm An Introduction to Programming with C++, Fifth Edition

  26. Desk-Checking the Algorithm (continued) An Introduction to Programming with C++, Fifth Edition

  27. Desk-Checking the Algorithm (continued) • Valid data is data that the programmer is expecting the user to enter • Invalid data is data that he or she is not expecting the user to enter • You should test an algorithm with invalid data • Users may make mistakes when entering data An Introduction to Programming with C++, Fifth Edition

  28. The Gas Mileage Problem An Introduction to Programming with C++, Fifth Edition

  29. The Gas Mileage Problem (continued) • After planning the algorithm, you desk-check it: An Introduction to Programming with C++, Fifth Edition

  30. Summary • Problem-solving typically involves analyzing the problem, and then planning, reviewing, implementing, evaluating, and modifying (if necessary) the solution • Programmers use tools (IPO charts, pseudocode, flowcharts) to help them analyze problems and develop algorithms • During analysis, you determine the output and input • During planning, you write the steps that will transform the input into the output An Introduction to Programming with C++, Fifth Edition

  31. Summary (continued) • After the analysis and planning, you desk-check the algorithm • Follow each of the steps in algorithm by hand • Coding refers to translating the algorithm into a language that the computer can understand • Before writing an algorithm, consider whether you have already solved a similar problem An Introduction to Programming with C++, Fifth Edition

  32. Application Lesson: Using the First Steps in the Problem-Solving Process • Lab 2.1: Stop and Analyze • Lab 2.2: • Create a program that the salesclerks can use to calculate and display the required number of rolls • Lab 2.3: • The program must now display the number of single and double rolls of wallpaper • Lab 2.4: Desk-Check Lab • Lab 2.5: Debugging Lab An Introduction to Programming with C++, Fifth Edition

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