Part 1. create a new Java application called "CheckString" (without the quotation marks) according to the following guidelines.
** Each method below, including main, should handle (catch) any Exceptions that are thrown. ** ** If an Exception is thrown and caught, print the Exception's message to the command line. **
1. Write a complete Java method called checkWord that takes a String parameter called word, returns nothing, and is declared to throw an Exception of type Exception. In the method, check if the first character of the parameter is a letter. If it is not a letter, the method throws an Exception of type Exception with the message of: "This is not a word."
2. Write a complete Java method called getWord that takes no parameters and returns a String. The method prompts the user for a word, and then calls the checkWord method you wrote in #1 above, passing as a parameter the word the user provided as input. Make sure the getWord method handles the Exception that may be thrown by checkWord.
3. Write a complete Java method called writeFile that takes two parameters: an array of Strings (arrayToWrite) and a String (filename). The method writes the Strings in the arrayToWrite array to a text file called filename (the parameter), with each String on a separate line.
4. Write a complete Java method called readFile that takes a String as a parameter (filename) and returns an ArrayList of Strings (fileContents). The method reads the text file identified by the filename parameter and populates the ArrayList with an element for each line in the text file.
5. In your main method, do the following in the order specified:
1. Call the getWord method you wrote in #2 above and print the result to the command line.
2. Create an array of Strings called testData and populate it with at least three elements.
3. Call the writeFile method you wrote in #3 above passing the array you created in #5.2 and the String "data.txt".
4. Call the readFile method you wrote in #4 above to read the file you wrote in #5.3. Assign the result of readFile to an ArrayList variable in main called fileContents.
5. Write a loop to print the contents of the fileContentsArrayList to the command line.
Part 2.
Create a new Java application called "WeightedAvgDataAnalyzer" (without the quotation marks), that modifies the DataAnalyzer.java in Horstmann Section 7.5, pp. 350-351 according to the specifications below.
The input file should be called 'data.txt' and should be created according to the highlighted instructions below. Note that even though you know the name of the input file, you should not hard-code this name into your program. Instead, prompt the user for the name of the input file.
The input file should contain (in order): the weight (a number greater than zero and less than or equal to 1), the number, n, of lowest numbers to drop, and the numbers to be averaged after dropping the lowest n values.
You should also prompt the user for the name of the output file, and then print your results to an output file with the name that the user specified.
- Your program should allow the user to re-enter the input file name if one or more of the exceptions in the catch clauses are caught.
- Your methods for getting data and printing results should each throw a FileNotFoundException which should be caught in the main method.
- Use try-with-resources statements. in your methods for getting and printing the data, and so avoid the need to explicitly close certain resources.
- In your readData method, use hasNextDouble to check ahead of time whether there's a double in the data. That way when you try to get the nextDouble, your code won't throw a NoSuchElementException.
You can use a writeFile method that does all the work (i.e., does not call a writeData method the way that Horstmann'sreadFile method calls a readData method). Use a try-with-resources statement in your writeFile method when creating a new PrintWriter.
The inputValues come from a single line in a text file (data.txt) such as the following:
0.5 3 10 70 90 80 20
The output in the output file must give the weighted average, the data and weight that were used to calculate the weighted average, and the number of values dropped before the weighted average was calculated.
Your output should look very much like the following: "The weighted average of the numbers is 42.5, when using the data 10.0, 70.0, 90.0, 80.0, 20.0, where 0.5 is the weight used, and the average is computed after dropping the lowest 3 values."
Write the output to a file with the filename that the user chose to name the output file (e.g., output.txt). Don't hard-code the output file name in your program.
Creating the Input File
To create the input file, while in NetBeans with your project open, first click to highlight the top-level folder of your project, which should be called WeightedAvgDataAnalyzer.
Then from the File menu do this:
File->New File
Keep the Project name at the top; keep Filter blank
Categories choose Other (at the bottom of the categories list)
File Types choose Empty File (at the bottom of the files list)
Next->
FileName: data.txt
Folder: this should be blank; if it's not, delete whatever's there.
Finish
In the empty file data.txt that you just created, add a single line of data like that shown in the example above, where the weight is a double (greater than 0.0 and less than or equal to 1.0) and the other numbers are the number, n, of lowest values to drop and then the numbers to be averaged after dropping the lowest n values.