Reading numbers from text files in Java

[Toramana]

Although, I am in enginnering line, I enjoy programming a lot (EE has got a connection with programming). In my spare time, I do fun programming. Below is Java code of an FSM (Finite State Machine) for identifying and reading numbers from a text file. It strips every thing off (e.g. white space, line feeds, carriage returns, text, or any character) and just reads numbers (integer and real).

Although not very neatly designed, it will never fail you.

public static double readValue() throws FileNotFoundException, IOException {

String myString = "";
String chString = "0123456789.";
int state = 1;
double value;

do
{

char buffer = (char)fptr.read();
if(chString.indexOf(buffer) == -1)
{

if((state == 1) | (state == 2))
state = 2;

if(state == 3)
{

value = Double.parseDouble(myString);
break;

}
}
if(chString.indexOf(buffer) >= 0 && (state == 1) | (state == 2) | (state == 3))
{

myString = (new StringBuilder()).append(myString).append(buffer).toString();
state = 3;

}

} while(true);

return value;

}

fptr is the handle of the text file you would be reading data from. It is a globally defined variable of type FileInputStream with definition given below.

FileInputStream fptr = new FileInputStream(new File("C:/Files/ABC.txt"));

ABC.txt is the file name to be read from. If locally defined in another function and passed as parameter to the FSM above, then the FSM function header would look like below.

public static double readValue(FileInputStream fptr) throws FileNotFoundException, IOException

[Talal]

and u can do this with a single line in matlab with a netlist :|

[Toramana]

and u can do this with a single line in matlab with a netlist :|

Yes, but such standard tools are not adequate for tokenizing plain text or data e.g., breaking the string {(56+78/89)+678.90*5^2} into individual categories (as required in language processing) as below,

{ left braces
} right braces
( left parenthesis
) right parenthesis
+ addition operator
*multiplication operator
/division operator
^ exponentiation operator
56 78 89 678 5 2 integer numbers
678.90 real number

java.util has got classes e.g. tokenizer, scanner, etc. that do simple lexical taks but cannot handle complex tokenization as above.

[Talal]

Yeah but believe me toramana you're not gonna be using java much in EE ..other than a first year java course it's all matlab..but you got good coding skills, Admin would be proud

[Admin Khan]

Talal, EE's can fill a CS job, but the same can't be said about a CS guy. Yes, I agree, CS majors might be stronger in programming but an EE with sufficient practice can be just as competitive. In the US, thousands of EE's are hired as Software Engineers. You do not need a degree in CS to be taken seriously. Generally, in interviews, they ask you to code a problem on the spot. If an EE can come up with the algorithm, the job might be his. EE's are applied Physicists so their versatility is unparalleled.

Canada unfortunately doesn't have as big of a market as the US, so the demand won't be as higher. Here in the US, E.E's get scooped instantly, along with CpE's and CS's.

[emkhan]

I love programming but don't know where to start from. I have tried some sources but could not get the basic idea what programming is and how is it done.

[Admin Khan]

I love programming but don't know where to start from. I have tried some sources but could not get the basic idea what programming is and how is it done.

Let's start from the basic. Start from Java, let's code a program that will find an even number.

First, download Eclipse IDE.
Once downloaded:
Click file>New Java project>
then,
file, new class.

Once you have eclipse up and running,

code the following:

import java.util.*;

public class PF {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int emkhan;

System.out.println("Hi, thanks to PF, I will learn how the algorithm of finding an even number");
emkhan=sc.nextInt();

if(emkhan%2==0){
System.out.println("The number, with all due respect, is even");
}
else{
System.out.println("Not even");
}
}
}




Start from Java, let's code a program that will find an even number.

[emkhan]

Thanks but it will not work I think. I need a proper way to go on that I have asked you in pm.

[Admin Khan]

Thanks but it will not work I think. I need a proper way to go on that I have asked you in pm.

Buy that book, and read it.

[emkhan]

Buy that book, and read it.

I will inshallah.
Thank you a lot.

[Talal]

emkhan i posted a website way back, it has tons of books on programming and stuff i believe its freebookspot.com

[Toramana]

public static int getSize(String inputString){

String myStr="";

for(int j=0; j < inputString.length();j++)

if ("1234567890".indexOf(inputString.charAt(j)) >= 0)
myStr+=inputString.charAt(j);

return Integer.parseInt(myStr);

}//getSize(String inputString)

If you want to return double-type number, then make the following changes...

change "1234567890" to "1234567890.E" and public static int to public static double and return Integer.parseInt(myStr) to return Double.parseDouble(myStr).

[Afghanistan2010]

i thought simple getting numbers from a "text area" or "text field" which is pretty much simple

iNumbers = double.parseDouble(txfAB.getText() )

anyway thank you.

[Toramana]

i thought simple getting numbers from a "text area" or "text field" which is pretty much simple

iNumbers = double.parseDouble(txfAB.getText() )

anyway thank you.

was talking of parsing strings or text files for numbers or other syntatic categories....not extracting values from text fields...

[Afghanistan2010]

Can you tell me how to get values from an array that i already have prepared.

like array [] = new String [3]

array [0]= "apple"
array [1] = "mango"
array [2] = "banana"

now i want to get one of the three fruits randomly