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Thread: Trying to trim and get length then parse from string into Double

  1. #1
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    Default Trying to trim and get length then parse from string into Double

    I have been trying to trim the and get the length and parse the string into a double from what the user entered to no avail. Any help would be much appreciated. Please bear with me as I am still very new to Java.

    So far what Ive done is asked the user to enter up to ten grades, I then added in there, if the user presses enter, then they are done entering. Then I would add up the grades and average them up and print it. I haven't added that coding in there yet, as I am still trying to trim, get length and parse the string into a double.

    I know, It would make sense to read doubles from the user, but my instructor specifically asked that we read strings then convert to doubles if and only if the user entered a length > 0 of which I already established into my code.

    So I am having troubles trying to trim, get length then parsing into doubles, if you could help me with that, that would be great!

    import java.util.*;
    import java.io.*;
    public class Grades {
     
    	public static void main(String[] args)throws IOException {
     
       	   double validGrades = 0;
    	   double d = 0;
    		double total = 0;
    		final int SIZE = 10;
    		boolean exit = false;
    		int count = 0;
    		String gradesEntered;
     
    		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
    		String[ ] grades = new String[SIZE];
    		String[ ] trimmedGradesEntered = new String[grades.length];
     
    		System.out.println("Please enter up to 10 grades and press enter to finish.");
     
     
    		while((count < SIZE) && (exit == false)){
    			System.out.print("Grade " + (++count) + ": ");
    			gradesEntered = bf.readLine( ) ;
    			if(gradesEntered.length() < 1){
    				exit = true;
     
    			}
    		}
     
    	}
    }


  2. #2
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    Default Re: Trying to trim and get length then parse from string into Double

    Take a look at :
    String (Java Platform SE 6)
    and
    Double (Java 2 Platform SE v1.4.2)

    Here's an small example

       try{
    	   String grade = bf.readLine().trim();
    	   double gradeDouble = Double.parseDouble(grade);
    	}catch(NumberFormatException exF){
    		//Handle an incorrect string
    	}


    BTW I think that's not a collection and generics issue

  3. #3
    Member Chris.Brown.SPE's Avatar
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    Default Re: Trying to trim and get length then parse from string into Double

    Writing code is your job, helping you fix and understand it is mine.

    <-- Be sure to thank and REP (Star icon) those who have helped you. They appreciate it!

  4. The Following User Says Thank You to Chris.Brown.SPE For This Useful Post:

    copeg (March 27th, 2013)

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    Administrator copeg's Avatar
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    Default Re: Trying to trim and get length then parse from string into Double

    Please read the forum rules. Not only is double posting against the rules, but it waste's the time of those trying to help - not the best way to get help from unpaid volunteers.

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