# Text Processing and More about Wrapper Classes - PowerPoint PPT Presentation

Text Processing and More about Wrapper Classes

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## Text Processing and More about Wrapper Classes

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1. Text Processing and More about Wrapper Classes

2. Contents • The Test Score Problem • Exercise

3. A. The Test Score Problem • Professor Harrison keeps her students’ test scores in a Microsoft Excel spreadsheet. Figure below shows a set of five test scores for five students. • In addition to manipulating the scores in Excel, Dr. Harrison wants to have a Java application that accesses them. Excel, like many commercial applications, has the ability to export data to a text file.

4. When the data in a spreadsheet is exported, each row is written to a line, and the values in the cells are separated by commas. For example, when the data shown in the Figure is exported, it will be written to a text file in the following format: 87,79,91,82,94 72,79,81,74,88 94,92,81,89,96 77,56,67,81,79 79,82,85,81,90 • This is called the comma separated value file format. When you save a spreadsheet in this format, Excel saves it to a file with the .csv extension. Dr. Harrison decides to export her spreadsheet to a .csv file, and wants to have a Java program that reads the file and calculates the score average for each student. Help her to do this task.

5. Solution • Problem Description • Preliminary Design • Test Cases • Developing the Test Class • Developing the Final Solution

6. 1. Problem Description • Calculate the score average for each student from a .csv file • Input: file name • Output: averages

7. 2. Preliminary Design

8. 3. Test Cases • Input: TestScores.csv • Output: { 86.6, 78.8, 90.4, 72.0, 83.4 }

9. 4. Developing the Test Class

10. 5. Developing the Final Solution

11. B. Exercise • The file SalesData.txt contains the dollar amount of sales that a retail store made each day for a number of weeks 1245.67,1490.07,1679.87,2371.46,1783.92,1461.99,2059.77 2541.36,2965.88,1965.32,1845.23,7021.11,9652.74,1469.36 2513.45,1963.22,1568.35,1966.35,1893.25,1025.36,1128.36 • Each line in the file contains seven numbers, which are the dales numbers for one week. The numbers are separated by a comma.

12. Develop a program that opens the file and processes its contents. The program should be able to calculate: • The total sales for each week • The average daily sales for each week • The total sales for all of the weeks • The average weekly sales • The week number that had the highest amount of sales • The week number that had the lowest amount of sales

13. References • Starting Out with Java. From Control Structures through Objects, Chapter 10. Tony Gaddis. Pearson Education International, 2010