problem with StringBuffer and Double

[Jesse Crockett]

here is the payroll.dat file I'm trying to read:

John Smith
9.45 40 15
Jane Doe
12.50 45 15
Harry Morgan
20.00 40 20
Carmen Martinez
25.00 35 25
Jacintha Washington
50.85 60 34


here is the code to read it and print the results:

Scanner scan = new Scanner(new FileReader("payroll.dat"));
 
while(scan.hasNextLine()) {
 
employeeName = new StringBuffer(scan.nextLine());
hourlyRate = new Double(scan.nextDouble());
hoursWorked = new Double(scan.nextDouble());
taxRate = new Double(scan.nextDouble());
 
 
printEmployeeInfo(employeeName, hourlyRate, hoursWorked, taxRate, grossAmount, netAmount);
 
}

As it is there it reads and prints the first employee and data but then I get an input mismatch exception trying to read the second employee, while this code does fine for all but the last (fifth) employee:

    while(scan.hasNextLine()) {
 
employeeName = new StringBuffer(scan.nextLine());
hourlyRate = new Double(scan.nextDouble());
hoursWorked = new Double(scan.nextDouble());
taxRate = new Double(scan.nextDouble());
scan.nextLine();
 
printEmployeeInfo(employeeName, hourlyRate, hoursWorked, taxRate, grossAmount, netAmount);
 
}

How do I get the fifth employee to print out. BTW, gross and net Amounts are previously set to 0.0 for this exercise.


Update: I found that if I use the latter code with an extra " " (space) after the last token in the file, the program works fine. I'm really confused. I could turn it in just like that, but I want to know what's going wrong with the while loop..

Update: then I remove the extra space at the end and for the fifth employee I get a NoSuchElementException: No Line Found


[ February 08, 2006: Message edited by: Jesse Crockett ]
[ February 08, 2006: Message edited by: Jesse Crockett ]

[Jeremy Tartaglia]

Sounds to me as if the data file and the algorithm don't match 100%. Try adding a new line to the end of the file:

employee1
hourlyRate hoursWorked tax
employee2
...
employee_n
hourlyRate hourseWorked tax
i'm insignficant.
 

And use the latter of your two algorithms. Or, just replace your scan.nextLine(); with if (scan.hasNextLine()) scan.nextLine();

I think one of those two should fix the problem.
[ February 08, 2006: Message edited by: Jeremy Tartaglia ]

[Jesse Crockett]

Here is the program. The previous problem was somehow fixed, and it's working now. This is supposed to print a chart with each employee's gross and net pay, then print a tally line with the total gross and net pay to all employees. It is printing "0.00" for each employees gross and net, but the total line is printing the correct total gross and net. I think there is a problem in main() between the methods processPay() and printEmployeeInfo(). What's the problem here?

 import java.util.*;
import java.io.*;
 
public class Payroll4 {
 
static final double FULL_TIME = 40.0;
static double totalGrossAmount = 0;
static double totalNetAmount = 0;
 

public static void main(String[] args) throws FileNotFoundException {
 
StringBuffer employeeName;
 
Double hourlyRate;
Double hoursWorked;
Double taxRate;
Double grossAmount = new Double(0.0);
Double netAmount = new Double(0.0);
 
instructions();
 
reportTitle();
 
makeFile();
 
Scanner scan = new Scanner(new FileReader("payroll.dat"));
 
while(scan.hasNextLine()) {
 
employeeName = new StringBuffer(scan.nextLine());
hourlyRate = new Double(scan.nextDouble());
hoursWorked = new Double(scan.nextDouble());
taxRate = new Double(scan.nextDouble());
scan.nextLine();
 
processPay(hourlyRate, hoursWorked, taxRate, grossAmount, netAmount);
 
printEmployeeInfo(employeeName, hourlyRate, hoursWorked, taxRate, grossAmount, netAmount);
 

}
 
scan.close();
 
totalAmounts();
 
}
 

public static void instructions() {
 
String instructionsStr = "\t\tInstructions for Payroll Report Program\n\n"
+ "This program calculates a paycheck for each employee.\n"
+ "A text file containing the following information will be created:\n"
+ "name, pay rate, hours worked, and tax percentage to be deducted.\n\n"
+ "The program will create a report in columnar format showing the\n"
+ "employee name, hourly rate, number of hours worked, tax rate,\n"
+ "groww pay, and net pay.\n\n"
+ "After all employees are processed, totals will be displayed,\n"
+ "including total gross amount and total net pay.\n";
 
System.out.print(instructionsStr);
System.out.println();
}
 
public static void reportTitle() {
 
String reportStr = "\t\t\t\tPayroll Report\n\n\n"
+ "Employee              Hourly   Hours     Tax     Gross     Net   \n"
+ "Name                   Rate    Worked    Rate    Amount   Amount \n"
+ "-------------------- -------- -------- -------- -------- --------\n";
 
System.out.print(reportStr);
 
}
 
public static void printEmployeeInfo(StringBuffer employeeName, Double hourlyRate, Double hoursWorked, Double taxRate, Double grossAmount, Double netAmount) {
 
System.out.printf("%-20s %8.2f %8.2f %8.2f %8.2f %8.2f%n", employeeName, hourlyRate, hoursWorked, taxRate, grossAmount, netAmount);
 
}
 
public static void processPay(Double hourlyRate, Double hoursWorked, Double taxRate, Double grossAmount, Double netAmount) {
 
final double OVERTIME_RATE = 1.5;
 
if(hoursWorked > FULL_TIME)
grossAmount = new Double((hourlyRate * FULL_TIME) + (hourlyRate * OVERTIME_RATE * (hoursWorked - FULL_TIME)));
else
grossAmount = new Double(hourlyRate * hoursWorked);
 
/** this line prints the grossAmount
but the value doesn't pass to printEmployeeInfo()
which is the next method call in main() */System.out.println(grossAmount);
 
totalGrossAmount = totalGrossAmount + grossAmount;
 
netAmount = new Double(grossAmount * taxRate / 100);
 
totalNetAmount = totalNetAmount + netAmount;
}
 
public static void totalAmounts() {
 
System.out.printf("Total                                           %8.2f %8.2f%n", totalGrossAmount, totalNetAmount);
System.out.println();
 
}
 
public static void makeFile() throws FileNotFoundException {
 
PrintWriter printF = new PrintWriter("payroll.dat");
 
printF.write("John Smith\n9.45 40 15\nJane Doe\n12.50 45 15\nHarry Morgan\n20.00 40 20\n"
+ "Carmen Martinez\n25.00 35 25\nJacintha Washington\n50.85 60 34 ");
 
printF.close();
 
}
 
}   

[Garrett Rowe]

public static void processPay(Double hourlyRate, Double hoursWorked, Double taxRate, Double grossAmount, Double netAmount) {
 
final double OVERTIME_RATE = 1.5;
 
if(hoursWorked > FULL_TIME)
grossAmount = new Double((hourlyRate * FULL_TIME) + (hourlyRate * OVERTIME_RATE * (hoursWorked - FULL_TIME)));
else
grossAmount = new Double(hourlyRate * hoursWorked);
 
/** this line prints the grossAmount
but the value doesn't pass to printEmployeeInfo()
which is the next method call in main() */System.out.println(grossAmount);
 
totalGrossAmount = totalGrossAmount + grossAmount;
 
netAmount = new Double(grossAmount * taxRate / 100);
 
totalNetAmount = totalNetAmount + netAmount;
}    

The problem here has to do with the scope of your variables. grossAmount is a local variable in this method. It is a copy of the grossAmount value in your main method, but the two variables are not the same. Therefore when you change grossAmount in this method, the grossAmount variable in your main method does not change. The workaround for this is either to declare class level static variables, or better yet write static methods return a value (and not void) and assign variables to those values in your main method

public static void main(String[] args)
{
   double grossAmount = calculateGrossAmount(hourlyRate, hoursWorked, taxRate);
   //... more stuff
}
 
public static double calculateGrossAmount(
     double hourlyRate, double hoursWorked, double taxRate)
{
   //... implement the method
   return grossAmount;
}