Assignment
Create a program called CalcWeightedAvgWithExceptions, and use try-catch-finally blocks in your methods, as in the examples try-catch-finally examples from the class notes for this lesson, which are also shown in the file 'TryCatchFinally.txt' available in this module.
The input file should be called 'data.txt' and should be created according to the highlighted instructions below. The input file should contain (in order): the weight, the number, n, of lowest numbers to drop, and the numbers to be averaged after dropping the lowest n values. See the example below. Also, your program should include methods for getting the input from the data.txt file, calculating the weighted average according to the data in the data.txt file, and printing the results to a user-designated output file.
Your main method should contain just three lines like these:
ArrayList inputValues = getData();
double weightedAvg = calcWeightedAvg(inputValues);
printResults(inputValues, weightedAvg);
The inputValues come from a single line in your data.txt file like the following:
0.5 3 10 70 90 80 20
The output file should contain something 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."
Creating the Input File
To create the input file, while in NetBeans with your project open, click to highlight the top-level folder of your project, which should be called CalcWeightedAvgWithExceptions. Then:
File-→New File...
Keep the Project name at the top; keep Filter blank
Categories → Other (at the bottom of the categories list)
File Types → 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 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. Also, instead of displaying the output to the console, let the user choose a file name (as in Horstmann's example), and write the output to a file with that user-supplied name (e.g., output.txt).