StringTokenizer: 'NoSuchElementException' 和其他一些问题

Question

In this program, I have a String with words separated by spaces and I want to remove a particular word and then print the new String. This is my code below:

import java.util.*;

class A
{
    public static void main()
    {
        String str="Monday Tuesday Wednesday";
        String newstr="";

        StringTokenizer S=new StringTokenizer(str);

        while(S.hasMoreTokens()==true)
        {
            if(S.nextToken().equals("Tuesday"))
            {
                continue;
            }
            else
                newstr=newstr+(S.nextToken()+" ");
        }

        System.out.println(newstr);
    }
}

In the above code, I want to delete the word 'Tuesday' from the String, and print the new String. But when I run the program, the following exception is thrown:

When I want to remove the word 'Wednesday' after changing the code, only 'Tuesday' is shown on Output screen. Likewise, when I want to remove 'Monday', only 'Wednesday' is shown as output.

I would really like some help on this so that I that I can understand the 'StringTokenizer' class better.

Thank You!

Answer 1

StringTokenizer.nextToken() increments the token upon each call. You should only call it once per loop, and save the value it returns in the local scope.

import java.util.StringTokenizer;

class A {

    public static void main(String[] args) {
        String str = "Monday Tuesday Wednesday";
        String newstr = "";
        StringTokenizer S = new StringTokenizer(str);
        while(S.hasMoreTokens() == true) {
            String day = S.nextToken();
            if(day.equals("Tuesday")) {
                continue;
            } else {
                newstr = newstr + (day + " ");
            }
        }
        System.out.println(newstr);
    }
}

returns Monday Wednesday

Answer 2

public class A {
    public static void main(String[] a) {
        String str = "Monday Tuesday Wednesday";
        String newstr = "";

        StringTokenizer S = new StringTokenizer(str," ");

        while (S.hasMoreTokens()) {
            String token = S.nextToken();
            if (token.equals("Tuesday")) {
                continue;
            } else
                newstr = newstr + (token + " ");
        }

        System.out.println(newstr);
    }
}

you have to take nextToken only once