Exceptions Aren't Always Errors Reading from Text File

Review the program Warning.java that reads in a file of student academic credit data. Each line of the input file

will contain the student name $($a single String with no spaces$),$ the number of semester hours earned $($an integer$),$

the total quality points earned $($a double$).$

Here is the students.dat data file:Smith $2783\mathrm{.}7$

Jones $2128\mathrm{.}35$

Walker $96182\mathrm{.}4$

Doe $60150$

Wood $100400$

Street $3357\mathrm{.}4$

Taylor $83190$

Davis $110198$

Smart $75292\mathrm{.}5$

Bird $84168$

Summers $5283\mathrm{.}2$The program should compute the GPA $($grade point or quality point average$)$ for each student $($the total quality

points divided by the number of semester hours$),$ and display the student name if the gpa is less than $2\mathrm{.}0.$ The

file Warning.java contains a skeleton of the program. After adding the comment section, do the following:

Add the code to calculate the gpa. $(3$ points$)$

Display the name if the gpa is less than $2\mathrm{.}0.(3$ points$)$

Test to ensure the output is accurate. $(3$ points$)$

Add code to catch the following exceptions:

A FileNotFoundException if the input file does not exist.

How will you test for this exception? $(3$ points$)$

A NumberFormatException if it can't parse an int or double when it tries to $-$ this indicates an error

in the input file format.

How will you test for this error? $(3$ points$)//$ Warning. java

$//****************************************************************************$

import java.util.Scanner;

import

java.io$.*$;

public class Warning

$1\{$ double qualityPts; $//$ number of quality points earned String name; Scanner inFile $=$ new Scanner$($new File$("$c:$\backslash \backslash$students$.$dat"$))$; $//$ Process the input file, one token at a time $\{//$ determine if the student is on warning. If so$,$ name $=$ inFile.next$()$; qualityPts $=$ Double.parseDouble$($inFile$.$next$())$; $//$ and statement to determine if the student name is listed. inFile.close$()$;$)$

$\}$

File CountLetters.java contains a program that reads a word from the user and prints the number of occurrences

of each letter in the word. In reviewing the code, note that the word is converted to all upper case first, then

each letter is translated to a number in the range $0.\mathrm{.}25($by subtracting $\text{'}$A$\text{'}$ or decimal $65)$ for use as an index. No

test is done to ensure that the characters are in fact letters.

Add the proper comment section, run CountLetters and enter a phrase, that is$,$ more than one word with

spaces or other punctuation in between. It should throw an ArrayIndexOutOfBoundsException, because

a non$-$letter will generate an index that is not between $0$ and $25.$ It might be desirable to allow non$-$letter

characters, but not count them. Of course, you could explicitly test the value of the character to see if it

is between $\text{'}$A$\text{'}$ and $\text{'}$Z$\text{'}.$ However, an alternative is to go ahead and use the translated character as an

index, and catch an ArrayIndexOutOfBoundsException if it occurs. Since you want don't want to do

anything when a non$-$letter occurs, the handler will be empty. Modify this method to do this as follows:

a$.$ Put the body of the first for loop in a try. $(5$ points$)$

b$.$ Add a catch that catches the exception, but don't do anything with it$.(5$ points$)$

Now modify the body of the catch so that it prints a useful message $($e$.$g$.,$ "Not a letter"$)$ followed by the

exception. $(5$ points$)//$ CountLetters.java

$//****************************************************************************$

import java.util.Scanner;

public class CountLetters

$1\{$ Scanner scan $=$ new Scanner$($System$.$in$)$; System.out.print$("$

Enter a single word $($letters only$)$: $")$; $//$convert to all upper case $//$count frequency of each letter in string counts$[$word$.$ charAt$($i$)-\text{'}$A$\text{'}]++$;