2

First of all this is a homework problem. I finished the program, and it runs fine; but I have a little side problem. The program is supposed to first read a txt file online, and gather all 50 states and their abbreviations. Next, I have to ask the user to enter in a valid state abbreviation. Once they do that, I have to read another txt file online, and return the two senators for their state.

The problem I'm having is that I want to loop the scanner asking the user to enter a state. If they enter an incorrect state, then I want to re-ask them. Right now, if I enter in a legit state, the program works fine. If I enter in an incorrect state, the program loops, and re-asks me to enter in another state. If I enter in an incorrect state, and then enter in a correct state, the program asks me to enter in another state, rather than continuing with the program. Any help please?

I think the problem is that when the program loops, it doesn't read:

if(stateAbbreviation.equals(abbreviation))
{
  state = splitData[0];
  abbrev = stateAbbreviation;
  found = true;
  break;
}

Again, making found always = false. 

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Scanner;

public class Senator
{
  static String abbrev; 
  static String state;

  public static void main(String[] args) throws IOException
  {
    // define our URL
    URL serviceURL = new URL("http://i5.nyu.edu/~cmk380/cs101/USStates.txt");

    // connect and obtain data from this URL
    Scanner input = new Scanner( serviceURL.openStream() );
    Scanner input1 = new Scanner(System.in);

    while(true)
    {
      boolean found = false;

      //Ask for state
      System.out.print("Enter state (abbreviation): ");
      String stateAbbreviation = input1.next();

      // read in our data
      while ( input.hasNext() )
      {
        // grab a line
        String data = input.nextLine();

        // split up the line based on the position of the commas
        String[] splitData = data.split(",");

        // grab out the abbreviation
        String abbreviation = splitData[1];  

        if(stateAbbreviation.equals(abbreviation))
        {
          state = splitData[0];
          abbrev = stateAbbreviation;
          found = true;
          break;
        }
      } 

      if (found == true)
      {
        // close our URL
        input.close();
        break;
      }
    }

    double numLines = 0;    

    // define our URL
    URL senatorURL = new URL("http://www.contactingthecongress.org/downloadsContactingCongress.db.txt");

    // connect and obtain data from this URL
    Scanner input2 = new Scanner( senatorURL.openStream() );

    // read in our data
    while ( input2.hasNext() )
    {
      // grab a line
      String data = input2.nextLine();

      if (numLines != 0)
      {
        // split up the line based on the position of the commas
        String[] splitData = data.split("\t");


        if(splitData[0].equals(abbrev+"SR"))
        {
          System.out.println("");
          System.out.println("State: " + state);
          System.out.println("");
          System.out.println("Senior Senator");
          System.out.println("Name: " + splitData[1]);

          //Try catch their information (exception raised if not found)
          try
          {
            System.out.println("Address: " + splitData[3]);
          }
          catch (Exception e)
          {
            System.out.println("Addrress unavailable.");
          }

          try
          {
            System.out.println("Phone: " + splitData[4]);
          }
          catch (Exception e)
          {
            System.out.println("Phone unavailable.");
          }

          try
          {
             System.out.println("Website: " + splitData[7]);
          }
          catch (Exception e)
          {
            System.out.println("Website unavailable.");
          }
          System.out.println("");
        }           

        if(splitData[0].equals(abbrev+"JR"))
        {
          System.out.println("Junior Senator");
          System.out.println("Name: " + splitData[1]);

          //Try catch their information (exception raised if not found)
          try
          {
            System.out.println("Address: " + splitData[3]);
          }
          catch (Exception e)
          {
            System.out.println("Addrress unavailable.");
          }

          try
          {
            System.out.println("Phone: " + splitData[4]);
          }
          catch (Exception e)
          {
            System.out.println("Phone unavailable.");
          }

          try
          {
            System.out.println("Website: " + splitData[7]);
          }
          catch (Exception e)
          {
            System.out.println("Website unavailable.");
          }
          System.out.println("");
        }

      }

      numLines ++; 
    }

    // close our URL
    input2.close();
  }
}
4

3 回答 3

3

You have two while and then you try to use a break to get out of it, but you're just getting out of the inner while.

To get out of both whiles, you need to change your program logic or use labels (yes, Java can use labels, and to break from an inner loop and of the outter loop at once is one of it's uses)

于 2012-12-10T18:56:29.200 回答
1

Another way you can do this is 

        public static boolean checkAbbreive(){
              while(true)
                {
                    boolean found = false;

                    //Ask for state
                    System.out.print("Enter state (abbreviation): ");
                    String stateAbbreviation = input1.next();

                    // read in our data
                    while ( input.hasNext() )
                    {
                        // grab a line
                        String data = input.nextLine();

                        // split up the line based on the position of the commas
                        String[] splitData = data.split(",");

                        // grab out the abbreviation
                        String abbreviation = splitData[1];  

                        if(stateAbbreviation.equals(abbreviation))
                        {
                            state = splitData[0];
                            abbrev = stateAbbreviation;
                            found = true;
                            return found;
                        }

               }
         if (checkAbbreive() == true)
            {
            // close our URL
            input.close();
            break;
            }

    }
}

Notice both while loops are encased in a function and there is a return found command after found = true

于 2012-12-10T18:59:21.907 回答
0

I'm not sure, if this will work, but try to break out of both loops.

breakTheWholeWhileLoop:
while(true)
{
   //For this version, we won't need the boolean found 
   //since we'll break out of everything

   //Ask for state
   System.out.print("Enter state (abbreviation): ");
   String stateAbbreviation = input1.next();

   //Read in our data
   while(input.hasNextLine() )
   {
      //...

      if(stateAbbreviation.equals(abbreviation) )
      {
         state = splitData[0];
         abbrev = stateAbbreviation;
         input.close();

         //This piece of code will break out of the while(true) loop
         break breakTheWholeWhileLoop;
      }
   } //while input loop
} //while true loop

//Do the rest

Hopefully that'll help.

于 2012-12-10T18:59:58.367 回答