Java String function help needed

Question

I have a homework question from college that I am having trouble with and I was wondering if anyone could give me some advice on where to go with it. We are using Arrays, for loops, if else and Strings.

I have to create a programme to take in a number of peoples names then put them in an Array ( which I had no problem with) I then need to separate the names in the array according to the first letters of each name : AG in one array, letters HP in another and the rest in a final array.

I have been told to use a String Function for this but not to use lists or Char. This is the code I have so far :

import java.util.Scanner;

public class Party {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) 
{
   Scanner sc = new Scanner(System.in); // declaring scanner

   int numGuests; // declaring the variable for number of guests
    System.out.println("please enter the number of guests you are hosting : ");
    numGuests = sc.nextInt(); // scanner for user inout num of guests

    String[] names = new String[numGuests]; // string for number of guests

    System.out.println("Please enter names "); 

    for(int i = 0; i < names.length; i++) // for loop for inputing the names.
    {
        names[i] = sc.next();
    }
}    
}

Answer 1

Please Use below logic and get result according to your requirement..
package com.test;
public class Namessplite {
    public static void main(String args[]){
    String[] names={"ABC","CAD","JKL","MNO"}; // these are names for example
    String[] atog_group = new String[10];
    String[] gtopgroup=  new String[10];
    int j=0,k=0;
    for(int i=0;i<names.length;i++){
        if((int)names[i].charAt(0)<72 && (int)names[i].charAt(0)>64){
            atog_group[j]=names[i];
            j++;
        }else{
            gtopgroup[k]=names[i];
            k++;
        }
    }
    System.out.println("A TO G Names Are :: ");
        for(int m=0;m<j;m++){
            System.out.println(atog_group[m]);  
        }
                System.out.println("G TO P Names Are :: ");
        for(int m=0;m<k;m++){
            System.out.println(gtopgroup[m]);   
        }
    }
}

Answer 2

Java 8 Style:

private static void splitNamesToArray(String[] names) {

    String[] aToG = Arrays.stream(names).filter(n -> n.toUpperCase().charAt(0) >= 65 && n.toUpperCase().charAt(0) <= 71).toArray(String[]::new);
    String[] hToP = Arrays.stream(names).filter(n -> n.toUpperCase().charAt(0) >= 72 && n.toUpperCase().charAt(0) <= 80).toArray(String[]::new);
    String[] rest = Arrays.stream(names).filter(n -> n.toUpperCase().charAt(0) >= 81 && n.toUpperCase().charAt(0) <= 90).toArray(String[]::new);

    System.out.println("A to G: " + Arrays.toString(aToG));
    System.out.println("H to P: " + Arrays.toString(hToP));
    System.out.println("Rest: " + Arrays.toString(rest));
}