Make a custom name generator?

Question

For programming homework, I was asked to make a name generator for the TV show Babylon 5. The program is supposed to take in your first name, last name, favorite city, and a good friends first name.

First name: Last 3 letters of favorite city + first 3 letters of first name

Last name: Last 3 letter of friends name + first 4 letters of last name

Then the program is supposed to insert an apostrophe before the first consonant in each name (except for consonants at the start of the name, in that case, use the second).

I have got everything working except for the apostrophe insertion.

public class MMStarWarsNG {

    /**
     * @param c
     * @return
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc = new Scanner(System.in); //creates the scanner that allows user input

        System.out.print("What is your first name? ");
        String firstName = sc.nextLine(); //creates new line after user hits enter
        firstName = firstName.substring(0, 3); //locates the first three characters the the user typed. In this case the character are 0,1,2.

        System.out.print("What is your last name? ");
        String lastName = sc.nextLine();
        lastName = lastName.substring(0, 4); //takes the first 4 characters the the user typed, characters: 0,1,2,3

        System.out.print("What is your favorite city? ");
        String favCity = sc.nextLine();
        favCity = favCity.substring(favCity.length() - 3); //takes the final 3 characters that the user typed
        favCity = favCity.substring(0, 1).toUpperCase() + favCity.substring(1); //takes the first character typed and capatilizes it

        System.out.print("What is the first name of a good friend? ");
        String friend = sc.nextLine();
        friend = friend.substring(friend.length() - 3);
        friend = friend.substring(0, 1).toUpperCase() + friend.substring(1);

        String SWName = favCity + firstName + " " + friend + lastName;//adds all of the substrings together. The space after firstName is the space between the first and last name

        System.out.println(SWName); //prints the line above
    }

    public static boolean consonantFinder(char c) {

        String vowels = "euioa";

        for (int i = 0; i < vowels.length(); i++) {

            if (c == vowels.charAt(i)) {
                return false;
            }
        }
        return true;
    }

    public static int apostropheAdder(StringBuilder s) {
        //adds apostrophe
        int position;
        for (position = 0; position < s.length(); position++) { //linear search for the length of the string
            if (consonantFinder(s.charAt(position))) { //finds position
                if (position != 0) { //checks if position is the first letter
                    consonantFinder((char) position); //does consonantFinder on the position
                    if (consonantFinder((char) position) == true) { //adds apostrophe
                        s.insert(position, "'");
                        position++; //because of the randomness in my code, I've made it so that
                        //it can have more than one apostrophe
                    }

                }

            }
        }
        return position;
    }

}

Answer 1

Your main doesn't call the method apostropheAdder(). That a good place to start.

    import java.util.*;
public class MMStarWarsNG {

    /**
     * @param c
     * @return
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc = new Scanner(System.in); //creates the scanner that allows user input

        System.out.print("What is your first name? ");
        String firstName = sc.nextLine(); //creates new line after user hits enter
        firstName = firstName.substring(0, 3); //locates the first three characters the the user typed. In this case the character are 0,1,2.

        System.out.print("What is your last name? ");
        String lastName = sc.nextLine();
        lastName = lastName.substring(0, 4); //takes the first 4 characters the the user typed, characters: 0,1,2,3

        System.out.print("What is your favorite city? ");
        String favCity = sc.nextLine();
        favCity = favCity.substring(favCity.length() - 3); //takes the final 3 characters that the user typed
        favCity = favCity.substring(0, 1).toUpperCase() + favCity.substring(1); //takes the first character typed and capatilizes it

        System.out.print("What is the first name of a good friend? ");
        String friend = sc.nextLine();
        friend = friend.substring(friend.length() - 3);
        friend = friend.substring(0, 1).toUpperCase() + friend.substring(1);

        String SWName = favCity + firstName + " " + friend + lastName;//adds all of the substrings together. The space after firstName is the space between the first and last name
        
        StringBuilder SWNameWapos = apostropheAdder(SWName);

        System.out.println(SWNameWapos); //prints the line above
    }

    public static boolean consonantFinder(char c) {

        String vowels = "euioa ";

        for (int i = 0; i < vowels.length(); i++) {

            if (c == vowels.charAt(i)) {
                return false;
            }
        }
        return true;
    }

    public static StringBuilder apostropheAdder(String a) {
        StringBuilder s = new StringBuilder(a);
        //adds apostrophe
        int position;
        for (position = 1; position < s.length(); position++) { //linear search for the length of the string
            if (consonantFinder(s.charAt(position))) { //finds position
                s.insert(position, "'");
                position++;
            }
        }
        return s;
    }
}

Answer 2

First, it's confusing that consonantFinder returns false when a consonant found, so swap the return values.

Then, apostropheAdder could be fixed using spaceOccured flag:

public static int apostropheAdder(StringBuilder s) {
    int position;
    boolean spaceOccured = true;
    int lastSpacePosition = 0;
    for (position = 0; position < s.length(); position++) {
        if (s.charAt(position) == ' ') {
            spaceOccured = true;
            lastSpacePosition = position;
        }
        if (!spaceOccured) {
            continue;
        }
        if (consonantFinder(s.charAt(position))) {
            if (position == lastSpacePosition) {
                continue;
            }
            spaceOccured = false;
            s.insert(position, "'");
        }
    }
    return position;
}