修正Cramer法则计算中行列式为0的问题

import java.util.Scanner;

class CramersRule {
    // Numbers for the 3-Variable Linear Equation.
    private double a1, a2, a3;
    private double b1, b2, b3;
    private double c1, c2, c3;
    private double d1, d2, d3;

    CramersRule() {

    }

    // Sets the 1st Linear Equation.
    public void setLinearEquation1(double a1, double b1, double c1, double d1) {
        this.a1 = a1;
        this.b1 = b1;
        this.c1 = c1;
        this.d1 = d1;
    }

    // Sets the 2nd Linear equation.
    public void setLinearEquation2(double a2, double b2, double c2, double d2) {
        this.a2 = a2;
        this.b2 = b2;
        this.c2 = c2;
        this.d2 = d2;
    }

    // Sets the 3rd Linear Equation.
    public void setLinearEquation3(double a3, double b3, double c3, double d3) {
        this.a3 = a3;
        this.b3 = b3;
        this.c3 = c3;
        this.d3 = d3;
    }

    /*
     * Returns the 3x3 Determinant
     */
    public double getDeterminant() {
        double d = a1 * ((b2 * c3) - (b3 * c2)) - a2 * ((b1 * c3) - (b3 * c1)) + a3 * ((b1 * c2) - (b2 * c1));
        return d;
    }

    /*
     * Returns the 3x3 Determinant for x
     */
    public double getDx() {
        double x = d1 * ((b2 * c3) - (b3 * c2)) - d2 * ((b1 * c3) - (b3 * c1)) + d3 * ((b1 * c2) - (b2 * c1));
        return x;
    }

    /*
     * Returns the 3x3 Determinant for y
     */
    public double getDy() {
        double y = a1 * ((d2 * c3) - (d3 * c2)) - a2 * ((d1 * c3) - (d3 * c1)) + a3 * ((d1 * c2) - (d2 * c1));
        return y;
    }

    /*
     * Returns the 3x3 Determinant for z
     */
    public double getDz() {
        double z = a1 * ((b2 * d3) - (b3 * d2)) - a2 * ((b1 * d3) - (b3 * d1)) + a3 * ((b1 * d2) - (b2 * d1));
        return z;
    }
}

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

        CramersRule CR = new CramersRule();
        System.out.print("Enter 4 numbers for the first equation (ie. 1 2 3 4): ");
        CR.setLinearEquation1(input.nextDouble(), input.nextDouble(), input.nextDouble(), input.nextDouble());

        System.out.print("Enter 4 numbers for the second equation (ie. 1 2 3 4): ");
        CR.setLinearEquation2(input.nextDouble(), input.nextDouble(), input.nextDouble(), input.nextDouble());

        System.out.print("Enter 4 numbers for the third equation (ie. 1 2 3 4): ");
        CR.setLinearEquation3(input.nextDouble(), input.nextDouble(), input.nextDouble(), input.nextDouble());

        System.out.println("The answer of the 3x3 Determinant is " + CR.getDeterminant());
        if (CR.getDeterminant() == 0) {
            System.out.println("Cramers Rule does not apply.");
        } else {
            double x = CR.getDx() / CR.getDeterminant();
            double y = CR.getDy() / CR.getDeterminant();
            double z = CR.getDz() / CR.getDeterminant();

            System.out.println("The solution set is (" + x + ", " + y + ", " + z + ")");
        }
    }
}