another i/o question

[Jason Mackie]

if i have to input 5 separate lines of code like:

Smith 27 83.7
Jones 21 28.35
Walker 96 182.4
Doe 60 150
Wood 100 400

how would i be able to put smith, 27, and 83.7 in separate variables?

here is my code so far...

import java.util.StringTokenizer;
import java.io.*;
import java.util.*;
 
public class Warning
{
// --------------------------------------------------------------------
//   Reads student data (name, semester hours, quality points) from a 
//   text file, computes the GPA, then writes data to another file
//   if the student is placed on academic warning.
// -------------------------------------------------------------------- 
public static void main (String[] args)
{
Scanner inFile;
PrintWriter outFile;
String name, inputName = "students.dat";
String outputName = "warning.dat";
int creditHrs;         // number of semester hours earned
double qualityPts;     // number of quality points earned
double GPA;            // grade point (quality point) average
 
try 
{
// Set up the input file stream
inFile = new Scanner(new FileInputStream(inputName));
 
// Set up the output file stream
outFile = new PrintWriter(new FileOutputStream(outputName));
 
// Print a header to the output file
outFile.println ();
outFile.println ("Students on Academic Warning");
outFile.println ();
 
// Process the input file, one line at a time
while (inFile.hasNextLine()){
String line = inFile.next();
 
// Get the credit hours and quality points and
// determine if the student is on warning. If so,
// write the student data to the output file.

there is more at the bottom but that is not important! I just need some guidance as to how to read a line of code from a file and then put the 3 different variables in their corresponding variables (im looking for help with the last comment in the snippet of code)

[Ulf Dittmer]

If you are certain that the names do not contain spaces you can use

String[] pieces = line.split(" ");

[Srikanth Ramu]

You could get the whole line and then split it instead of getting each elements. Hope this helps.

while(inFile.hasNextLine())
        {
            String line = inFile.nextLine(); //Getting the whole line with space separated
            String[] val = line.split(" ");
            for(int i=0; i<val.length;i++)
            {
                System.out.println("The value " + val[i]);
            }
        }

[Campbell Ritchie]

If you are using a Scanner, it has methods which allow you to get the next int, the next double or the next token. Have a look in its API documentation here.

CR

[Jason Mackie]

it seems to me that the whole "split" thing would work but how would i be able to store them in differnt variables?

in the file im inputing there are 3 "variables" per line. the first one is name which has no spaces, the second is an integer that is called creditHrs, and the last is a double called qualityPts. I was thinking of using an if statement like

if (______ == string or char){
name == _________;
}
else if (_______ == int){
creditHrs = _____________;
}
else if (_______ == double){
qualityPts = ___________;
}

is there any way to do that?

[fred rosenberger]

the API tells you that the split method returns an array of strings.

You know the [0]th element will have first token, or the name. the [1]st element will have the second token, or the int. the [2]nd element will have the double. write a statement for each that assigns or (parses and assigns) them to the variables you want.

[Jason Mackie]

sorry here is the code i just posted might be easier to read this way

if (______ == string or char)
{
     name == _________;
}
 
else if (_______ == int)
{
     creditHrs = _____________;
}
 
else if (_______ == double)
{
     qualityPts = ___________;
}

[Ulf Dittmer]

How about something like the following:

String[] pieces = line.split(" ");
String name = pieces[0];
int creditHrs = Integer.parseInt(pieces[1]);
double qualityPts = new Double(pieces[2]).doubleValue();

You really need to be sure that the names do not contain spaces, though.

[Jason Mackie]

i actually used the StringTokenizer to solve the problem...I tried messing around with "split" for a long while and was not able to come to a solution. Here was my finishing code:

//****************************************************************************
//Warning.java
 
//Reads student data from a text file and writes data to another text file.
//****************************************************************************
 
import java.util.StringTokenizer;
import java.io.*;
import java.util.Scanner;
 
public class Warning
{
// --------------------------------------------------------------------
//   Reads student data (name, semester hours, quality points) from a 
//   text file, computes the GPA, then writes data to another file
//   if the student is placed on academic warning.
// -------------------------------------------------------------------- 
@SuppressWarnings("hiding")
public static void main (String[] args)
{
Scanner inFile;
PrintWriter outFile;
String name, inputName = "students.txt";
String outputName = "warning.dat";
int creditHrs;         // number of semester hours earned
double qualityPts;     // number of quality points earned
double GPA;            // grade point (quality point) average
 
try 
{
// Set up the input file stream
inFile = new Scanner(new FileInputStream(inputName));
 
// Set up the output file stream
outFile = new PrintWriter(new FileOutputStream(outputName));
 
// Print a header to the output file
outFile.println ();
outFile.println ("Students on Academic Warning");
outFile.println ();
 
// Process the input file, one line at a time
while(inFile.hasNextLine())
{
String information = inFile.nextLine();
 
// Get the credit hours and quality points and
// determine if the student is on warning. If so,
// write the student data to the output file.
StringTokenizer info = new StringTokenizer(information);
name = info.nextToken();
creditHrs = Integer.parseInt(info.nextToken());
qualityPts = Double.parseDouble(info.nextToken());
 
GPA = qualityPts / creditHrs;
 
if (GPA < 1.5 && creditHrs < 30)
{
outFile.println(name + " " + creditHrs + " " + GPA);
}
else if (GPA < 1.75 && creditHrs < 60)
{
outFile.println(name + " " + creditHrs + " " + GPA);
}
else if (GPA < 2.0)
{
outFile.println(name + " " + creditHrs + " " + GPA);
}
}
 
// Close both file streams
inFile.close();
outFile.close();
}
 
catch (FileNotFoundException exception)
{
System.out.println ("The file " + inputName + " was not found.");
}
 
catch (IOException exception)
{
System.out.println (exception);
}
finally
{
System.out.println("File has been created");
System.exit(0);
}
}
}

thanks to everyone that helped...
Jason

[David McCombs]

Don't use StringTokenizer. For one thing String.split() is far simpler, and StringTokenizer is a legacy class, only kept around to not break older code.

From the StringTokenizer description in the API: "StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code."

http://java.sun.com/j2se/1.5.0/docs/api/index.html

Make sure you have the right regular expression as an argument in split, Passing " " as an argument to split should work just fine, unless the data is not in the format you expect.

[Jason Mackie]

right on...thanks