Dung Harrys CodeSnippet

import java.util.Scanner;

public class AlphabetSorting {
    private String name[] = new String[100];
    private int numberName = 0;

    public AlphabetSorting() {
        this.initialize();
    }

    private void initialize() {
        for(int i = 0; i < this.name.length; i ++) {
            this.name[i] = new String("");
        }
    }

    public void enterNames() {
        Scanner scanner = new Scanner(System.in);
        String temp = new String("");
        boolean flag = true;

        do {
            System.out.print("Enter number of the name you wanted to sort: ");
            temp = scanner.nextLine();

            for(int i = 0; i < temp.length(); i ++) {
                if((temp.charAt(i) <= '0') && (temp.charAt(i) >= '9')) {
                    flag = false;
                }
            }

            if(!flag) {
                System.out.println("**Error: Your entering is invalid. Enter again");
            } else {
                this.numberName = Integer.parseInt(temp);
                if(this.numberName > 100) {
                    System.out.println("**Error: Your number of names is greater than 100");
                }
            }
        } while((!flag) && (this.numberName > 100));

        System.out.println("Begin entering each name...");

        for(int i = 0; i < numberName; i ++) {
            System.out.print("Enter name " + (i + 1) + ": ");
            this.name[i] = scanner.nextLine();
        }

        System.out.println("Finish entering name part...");
    }

    private void swapNames(int firstIndex, int secondIndex) {
        String temp = new String("");

        temp = this.name[firstIndex];
        this.name[firstIndex] = this.name[secondIndex];
        this.name[secondIndex] = temp;
    }

    private int charAt(int nameIndex, int index) {
        if((index >= this.name[nameIndex].length()) || (nameIndex >= this.numberName)) {
            return 1;
        } else {
            return this.name[nameIndex].charAt(index);
        }
    }

    private void sortRange(int index, int head, int tail) {
        for(int i = head; i <= tail; i ++) {
            for(int j = i; j <= tail; j ++) {
                if(this.charAt(i, index) > this.charAt(j, index)) {
                    int firstSum = 0, secondSum = 0;
                    for(int m = 0; m < index; m ++) {
                        firstSum += this.charAt(i, m);
                        secondSum += this.charAt(j, m);
                    }
                    if(firstSum == secondSum) {
                        this.swapNames(i, j);
                    }
                }
            }
        }
    }

    private int getMaxLengthName() {
        int tmp = this.name[0].length();

        for(int i = 0; i < this.numberName; i ++) {
            if(this.name[i].length() > tmp) {
                tmp = this.name[i].length();
            }
        }

        return tmp;
    }

    public void sortAlphabet() {
        int maxLength = this.getMaxLengthName();
        int head, tail;
        char temp;

        this.sortRange(0, 0, this.numberName - 1);

        for(int j = 1; j < maxLength; j ++) {
            int i = 0;

            while(i < this.numberName) {
                head = i;

                temp = (char) this.charAt(i, j - 1);

                while(this.charAt(++ i, j - 1) == temp) {
                    if(i >= this.numberName - 1) {
                        i ++;
                        break;
                    }
                }

                tail = i - 1;

                this.sortRange(j, head, tail);
            }
        }
    }

    public void printNames() {
        for(int i = 0; i < this.numberName; i ++) {
            System.out.println("Name " + (i + 1) + ": " + this.name[i]);
        }
    }

    public static void main(String[] args) {
        AlphabetSorting sorter = new AlphabetSorting();
        sorter.enterNames();

        sorter.sortAlphabet();

        System.out.println("The result after sorting is: \n");

        sorter.printNames();
    }
}