Don`t understand why the last condition won`t verify

Question about the task

Find a substring

Java Multithreading, Level 2, Lesson 5

Under discussion

Please help me, i tried it with string.length()-1 and string.length() and I doesn`t work both ways. Greetings Fabian

The getPartOfString method must return the substring that begins with the character after the first space and ends with the end of the word that follows the 4th space.

Example:
"CodeGym is the best place to learn Java."

Result:
"is the best place"

Example:
"Amigo and Diego are best friends!"

Result:
"and Diego are best"

If the input data is invalid, throw a StringTooShortException (create an exception).

Requirements:

The StringTooShortException class must be a child of the RuntimeException class.
The getPartOfString method must have a String parameter.
If invalid data is passed to the getPartOfString method, a StringTooShortException should be thrown.
The getPartOfString method must return the substring that begins with the character after the first space and ends with the word that follows the 4th space.

package com.codegym.task.task22.task2202; /* Find a substring */ public class Solution { public static void main(String[] args) { try { System.out.println(getPartOfString("CodeGym is the best place to learn Java.")); } catch( Exception e) { throw new StringTooShortException(); } } public static String getPartOfString(String string) throws StringTooShortException { if(string==null) { throw new StringTooShortException(); } int spaceCount = 0; for (char c : string.toCharArray()) { if (c == ' ') { spaceCount++; } } if(spaceCount<4) { throw new StringTooShortException(); } int firstCharacterIndex=string.indexOf(" ")+1; int lastCharacterIndex=string.lastIndexOf(" ")+1; return string.substring(firstCharacterIndex,string.length()); } public static class StringTooShortException extends RuntimeException { } }

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horst

Level 26 , Not in list

26 October 2020, 14:41

It seems that in line 46 you are printing the substring from the first space (looks correct to me) to the very end of the string, which can't be correct, because the string may well have more than four spaces in total. (Even if it has exactly four spaces, you need to cut off the last word of the string that comes right after the fourth space) Obviously, you will need to find out the position/index of the fourth space in the string to make this the end position of your substring. You can now try to expand the "space-count"-part of your method (l 26ff.) with an additional variable holding the index of the current space and store it as soon as your counter hits "4". PS: Just as an alternative approach I'd like to mention that instead of all this you could use the split()-method to split your String into an array of its individual words. For example:

String str =  "Amigo and Diego are best friends!";
String[] array = str.split(" "); // use the space character as the spliiter

Your array now looks like this: array[0] = "Amigo" array[1] = "and" array[2] = "Diego" and so on... Then you can access array-indices 1 to 4 to recreate the message.