Counting words in strings that only contain letter in java

Question

i have been given an problem to solve in class where i need to take in a string and then print out how many numbers are in the string. A word is defined as only containing the characters a-z and A-Z. I cannot use split().

public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);
    String sentence;
    String currentWord;
    int wordCount;
    int spacePos;
    int validChar;

    System.out.print("Please enter a sentence: \n");
    sentence = input.nextLine() + " ";
    spacePos = sentence.indexOf(" ");
    wordCount = 0;
    currentWord = sentence.substring(0, spacePos);
    validChar = 0;

    while(spacePos > -1)
        {
            for(int i = 0; i < currentWord.length(); i++)
                {
                    int j = currentWord.charAt(i);
                    if( j >= 'a' && j <= 'z' || j >= 'A' && j <= 'Z')
                        {
                            validChar++;
                        }
                }
            if( validChar == currentWord.length() )
                {
                    wordCount++;
                }
            currentWord = currentWord.substring(spacePos);
        }
    System.out.println("The number of words in this string is " + wordCount + "\n\n");
    input.close();
}
}

}

this is what i have so far but i am getting an error saying that currentWord = currentWord.substring(spacePos); is

java.lang.StringIndexOutOfBoundsException: String index out of range: -5

EDIT: My problem wasnt just with the error but with the logic too, but i spent a good couple hours on paper and rewrote it from scratch and solved it. Here is my updated code without using .split().

public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);
    String currentWord;
    String sentence;
    int spacePos;
    int wordCount;
    int validChar;

    System.out.print("Please enter a sentence: \n");
    sentence = input.nextLine() + " ";
    spacePos = sentence.indexOf(" "); 
    currentWord = sentence.substring(0, spacePos); 
    wordCount = 0;
    validChar = 0; 

    if( spacePos == 0 )
        {
            spacePos = 1;
        }//end of if
    for( int i = 0; i < sentence.length(); i++ )
        {
            //  VALIDATES IF A WORD IS A WORD
            for(int j = 0; j < currentWord.length(); j++)
                        {
                            if( currentWord.charAt(j) > 'a' && currentWord.charAt(j) < 'z'
                                || currentWord.charAt(j) > 'A' && currentWord.charAt(j) < 'Z')
                                {
                                    validChar++;
                                }//end of if
                            if( validChar == currentWord.length() )
                                {
                                    validChar = 0;
                                    wordCount++;
                                }//end of if
                        }//end of for
            // ROMOVES PREVIOUS WORD
            sentence = sentence.replace(currentWord + " ", "");
            currentWord = sentence.substring(0, spacePos);
            spacePos = sentence.indexOf(" ") + 1; 
        } //end of for
    System.out.println("\n\n FINAL WORD COUNT --->\t\t" + wordCount + "\n");
    input.close();
}

Possible duplicate of [What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?](https://stackoverflow.com/questions/5554734/what-causes-a-java-lang-arrayindexoutofboundsexception-and-how-do-i-prevent-it) — ljeabmreosn, Nov 15 '18 at 17:21

score -1 · Answer 1 · answered Nov 15 '18 at 17:06

Below logic should work for you,

public static void main(String[] args)
    {
        int wordCount=0;
        StringBuffer newDummy=new StringBuffer();

        String dummy = "1223fgfdfsdfhi sdfsdfh8678 df 435";

                for(int i = 0; i < dummy.length(); i++)
                    {
                        if (Character.isDigit(dummy.charAt(i)))
                        {
                            wordCount++;
                        }else{
                            newDummy.append(dummy.charAt(i));
                        }
                    }

        System.out.println("The number of words in this string is " + wordCount + "\n\n");
        System.out.println("new String-->"+newDummy);
    }

Counting words in strings that only contain letter in java

1 Answers1