Java 等比數列

輸入幾組數列
輸入4個數字，並推算出第5個數字

輸入:
2
1 2 3 4
1 2 4 8

輸出:
1 2 3 4 5
1 2 4 8 16

import java.util.Scanner;
import java.io.*;

public class Test{
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int [][] b;
        b = new int [a][5];

        for(int i = 0; i < a; i++){
            for(int j = 0; j < 4; j++){
                b[i][j] = sc.nextInt();
            }
            if( b[i][3]-b[i][2] == b[i][1]-b[i][0] ){
                b[i][4] = b[i][3] + ( b[i][3]-b[i][2] );
            }
            else{
                b[i][4] = b[i][3] * (b[i][3] / b[i][2]);
            }
            for(int x = 0; x < 5; x++){
                System.out.print(b[i][x] + " ");
            }
            System.out.println();
        }
    }
}