Read in From file to array and convert to double

[jlwhite]

I am just doing challenges with friends and I am trying to input points from a file that represent coordinates for a triangle. The program works if I hard code in the values for the points. I am reading in the file using DataInputStream and saving it to a string variable. Then converting it to double using parseDouble and assigning it to an array. Then I assign the elements of the array to individual points. But for some reason it says the points are 0. I know the readLine is depricated but using readUTF doesn't work either. Are there any suggestions? I have included the entire code below.

import static java.lang.Math.sqrt;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class MyTraingleReadIn {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
double x1;
double x2;
double x3;
double y1;
double y2;
double y3;

double[] array;
array = new double[6];
int counter = 0;
File file = new File("MyFile.txt");
FileInputStream fis = null;
BufferedInputStream bis = null;
DataInputStream dis = null;

try {
fis = new FileInputStream(file);

// Here BufferedInputStream is added for fast reading.
bis = new BufferedInputStream(fis);
dis = new DataInputStream(bis);

// dis.available() returns 0 if the file does not have more lines.
while (dis.available() != 0) {

// this statement reads the line from the file and print it to
// the console.
String strIn = dis.readLine();
array[counter] = Double.parseDouble(strIn);
counter ++;
}

// dispose all the resources after using them.
fis.close();
bis.close();
dis.close();

} catch (FileNotFoundException e) {
// e.printStackTrace();
} catch (IOException e) {
// e.printStackTrace();
}
// initialize points
x1 = array[0];
//System.out.print(x1);
x2 = array[1];
x3 = array[2];
y1 = array[3];
//System.out.print(y1);
y2 = array[4];
y3 = array[5];

//declare sides and points
double side1;
double side2;
double side3;
double result;

side1 = sides(x1,x2,y1,y2);
side2 = sides(x1,x3,y1,y3);
side3 = sides(x2,x3,y2,y3);

if(isValid(side1,side2,side3)){
result = area(side1,side2,side3);
System.out.println(result);
}else{
System.out.println("Input is invalid!");
}
}
//comment: returns true if the sum of any two sides is greater than the third side
public static boolean isValid(double side1, double side2, double side3){
boolean bln = false;
double sum1 = side1 + side2;
double sum2 = side1 + side3;
double sum3 = side2 + side3;
if(sum1 > side3){
bln = true;
}else if (sum2 > side2){
bln = true;
}else if(sum3 > side1){
bln = true;
}else{
bln = false;
}
return bln;


}
//comment: returns area of the triangle
public static double area(double side1, double side2, double side3){
double s;
double area;
s = (side1 + side2 + side3)/2;
area = sqrt(s*(s - side1)*(s - side2)*(s - side3));

return area;

}
//determine sides
public static double sides(double x1,double x2,double y1,double y2){
double side;
side = distance(x1,x2,y1,y2);
return side;
}

//Distance formula
public static double distance(double x1, double x2, double y1, double y2){
double distance;
distance = sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
return distance;
}

}

[Junky]

InputStreams are intended to read raw bytes and not textual data. Try using the Scanner class instead.

[Eranga]

And once you read the inputs as strings, use wrappers to convert into double. But the representation (or the format) should be in digits or a pattern like doubles. Otherwise you end-up with format exception.

[jlwhite]

ok well I am new to java programming and I don't know all the syntax and functions and stuff but this is what i'm trying to do to convert and it gives me a format exception

while (scanner.hasNextLine()) {
String strIn = scanner.nextLine();
array[counter] = Double.valueOf(strIn.trim());

[jlwhite]

Nevermind it worked. The Text file was UTF-8 encoded and I had to change it to ANSI. Thanks for the help!

[Eranga]

ok well I am new to java programming and I don't know all the syntax and functions and stuff but this is what i'm trying to do to convert and it gives me a format exception

As I explain in my previous post, format can cause lots of issues. So handling them is very important. With try-catch you can do it easily, as you did.

However, don't these kind of thin in try block,

// dispose all the resources after using them.
fis.close();
bis.close();
dis.close();

due to some errors it may not release. :) Do them in finally block to be in safe side.

[Eranga]

Nevermind it worked. The Text file was UTF-8 encoded and I had to change it to ANSI. Thanks for the help!

Good to see.

Why don't you mark the thread solved then?