0 
public static void displayWords(String line)
{
  // while line has a length greater than 0
  //   find the index of the space.
  //   if there is one,
  //    print the substring from 0 to the space
  //    change line to be the substring from the space to the end
  //   else
  //    print line and then set it equal to the empty string

}
  line = "I love you";
  System.out.printf("\n\n\"%s\" contains the words:\n", line );
  displayWords(line);

Hi, i'm having trouble with the above code, it;s a practice problem but "change line to be the substring from the space to the end" really confuses me. I know how to find the index of space and printing the string from the beginning to the index.

Expected Output:

I
love
you
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6
  • 2
    Did you look at the substring() method? Commented Sep 21, 2014 at 4:07
  • I can't add other methods, it's a practice problem where you have to work with the snippet given to you. Commented Sep 21, 2014 at 4:09
  • 2
    he means docs.oracle.com/javase/1.5.0/docs/api/java/lang/… Commented Sep 21, 2014 at 4:10
  • I have to be able to use any other strings like "John went to the store", and the expected output be "John \n went \n to \n the \n store". I could use substring method to print the words, but it wouldn't be applicable to other strings. Commented Sep 21, 2014 at 4:14
  • You can run your string through a scanner. Commented Sep 21, 2014 at 4:17

2 Answers 2

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1

SLaks is recommending in his comment you to use the substring() method. Checking the API documentation for String:

public String substring(int beginIndex, int endIndex)

Returns a new string that is a substring of this string. The substring begins at the specified beginIndex and extends to the character at index endIndex - 1. Thus the length of the substring is endIndex-beginIndex.

Examples:

  • "hamburger".substring(4, 8) returns "urge"
  • "smiles".substring(1, 5) returns "mile"

So, consider this:

public static void displayWords(String line) {
    while(line.length() > 0) { // This is the first part (the obvious one)
        /*
           You should do something here that tracks the index of the first space 
           character in the line. I suggest you check the `charAt()` method, and use 
           a for() loop.
           Let's say you find a space at index i
         */
         System.out.println(line.substring(0,i)); // This prints the substring of line
                                                  // that goes from the beginning
                                                  // (index 0) to the position right
                                                  // before the space
         /*
           Finally, here you should assign a new value to line, that value must start
           after the recently found space and end at the end of the line.
           Hint: use substring() again, and remember that line.lengh() will give you
                 the position of the last character of line plus one.
          */
    }
}

You've had enough time... and I'm feeling generous tonight. So here is the solution:

public static void displayWords(String line) {
    int i; // You'll need this
    while(line.length() > 0) { // This is the first part (the obvious one)
        /*
           Here, check each character and if you find a space, break the loop
         */
        for(i = 0; i < line.length(); i++) {
            if(line.charAt(i) == ' ') // If the character at index i is a space ...
                break;                // ... break the for loop
        }
        System.out.println(line.substring(0,i)); // This prints the substring of line
                                                 // that goes from the beginning
                                                 // (index 0) to the position right
                                                 // before the space
        /*
          Here, the new value of line is the substring from the position of the space
          plus one to the end of the line. If i is greater than the length of the line
          then you're done.
         */
        if(i < line.length())
            line = line.substring(i + 1, line.length());
        else
            line = "";
    }
}

After reading your question again, I realised that it should be a recursive solution... so here is the recursive approach:

public static void displayWords(String line) {
    int i;
    for(i = 0; i < line.lengh(); i++) {
        if(line.charAt(i) = ' ')
            break;
    }
    System.out.println(line.substring(0, i);
    if(i < line.lengh())
        line = line.substring(i + 1, line.lengh();
    else
        line = "";
    if(line.lengh() > 0)
        displayWords(line);
}
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Comments

0

Another way of doing it.

public static void displayWords(String line)
{
  Scanner s = new Scanner(line)
  while (s.hasNext())
  {
    System.out.println(s.next())
  }
}

http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html < Use this for reference.

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1 Comment

I think that the OP is a beginner, and although this is a very easy way to do exactly what is needed, it's not quite what the OP needs. Sometimes, when learing, it's a good thing to do it "the hard, not quite efficient way" to properly appreciate the "easy, efficient, clean and elegant way"

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