Java Help in storing a Buffer

[anonb]

Need help adding a buffer. Please see below:

1 – Read reference string
A reference string will be read from the keyboard and stored in a buffer. Each value of the reference string will be verified and validated (or rejected).
The user will be first asked to enter the length of the reference string, and then the string itself will be entered.
2 – Generate reference string
A reference string will be randomly generated; the length of the reference string will be given by the user interactively. The string will be stored in a buffer.
Using options 1 and 2 more than once will result in overwriting the old reference string.
3 – Display current reference string
Will display the stored reference string; if there is no reference string stored yet, an error message will be displayed.

import java.util.Random;
import java.util.Scanner;

public class simulator {
    
   public static void main (String[] args)
    {
         
    int str_len=0;
    StringBuilder buffer = new StringBuilder(str_len);
    Scanner input = new Scanner(System.in);
    int choice;
    
    choice=menu(input);
    do
    {
    switch (choice)
    {
    //Exits Program
    case 0:
    System.out.println("This program will exit!");
    System.exit(0);
    break;
    //Enter length/reference value of string
    case 1:       
    //simulator test= new simulator();
    System.out.println("Please enter length of string "); 
    str_len=input.nextInt();
    System.out.println("Please enter reference string ");
    
    for (int i=0; i<=str_len-1;i++)
    {
    int[] count = new int[str_len];
    count[i] = input.nextInt();
       
    if (count[i]<0||count[i]>9)
    {
    System.out.println(count[i] + " is Rejected");
    }//ends if
    else if (count[i]>0||count[i]<9)
    {
    System.out.println(count[i] + " is Validated");
    //StringBuilder validate = new StringBuilder(count);
    }//ends if
    }//ends for
    break;
    
    case 2:
    //int str_len;
    //simulator test2= new simulator(str_len3);
    System.out.println("Please enter length of string "); 
    
    str_len=input.nextInt();
       //Math.random();
       Random random = new Random();
       for (int i=1; i<=str_len; i++)
       {
           System.out.println(random.nextInt(15));
       }//ends for
       //StringBuilder validate2 = new StringBuilder(str_len);
       System.out.println("validate is " + buffer);
       break;
       //display reference string
       case 3:
    
       break;
    
       }//ends switch
    choice=menu(input);
    }
    while(choice!=0);
    }//ends main
    //menu      
    public static int menu(Scanner input)
    {
    int n;
    System.out.println("MENU");
    System.out.println("0 - Exit ");
    System.out.println("1 - Read reference string ");
    System.out.println("2 - Generate reference string ");
    System.out.println("3 - Display current reference string ");
    n=input.nextInt();
    return n;
    }//ends menu
    
  }//ends class

[quad64bit]

Sounds like a homework dump. Please ask specific questions.

[anonb]

So how can I get case 2 see the string in case 1 and so forth?

[quad64bit]

When I read the #2 description, it implies to me that the string should be generated randomly and not given by the user in step 1. The only thing the user does is specify the length.

[anonb]

ok but case 3, says to display the current string. I have yet to figure that out. I cannot display the current string in 1 or 2 because the strings are local to those cases and cannot be accessed outside of those cases..

[quad64bit]

Do they have to be local?

[anonb]

No they do not have to be local.

[quad64bit]

Then make them instance variables. Then you can always retrieve whatever the current state of the variable is.

[anonb]

OK, I will try tonight once I get home.