[JAVA-PRACTICE] - Giải hệ phương trình bậc nhất (có khả năng thi kết thúc học phần >viết code + vấn đáp)

HePtB1.java

package ktpmk12b-ictu;
import java.util.Scanner;

/**
 *
 * @author HARD-Code
 */
public class HePtB1 {
    double a1, b1, c1;
    double a2, b2, c2;

    public void Input() {
        Scanner s = new Scanner(System.in);
        System.out.println("------------SSG-----------");
        System.out.println("Vao he so: a1, b1, c1 = ");
        a1 = s.nextDouble();       b1 = s.nextDouble();  c1 = s.nextDouble();
        System.out.println("--Het PT1. Moi ban Nhap PT2--");
        System.out.println("a2, b2, c2 = ");
        a2 = s.nextDouble();   b2 = s.nextDouble();        c2 = s.nextDouble();
        System.out.println("-------Hoan thanh Nhap-------");
        System.out.println("");
    }
   
   public void PpThe(){
        double b11=b1*a2;        
        double c11=c1*a2;       
        double b22=b2*a1;        
        double c22=c2*a1;
        
        double y = (c22-c11)/(b11-b22);
        System.out.println("y = "+y);
        double x = (-c11-b11*y)/(a1*a2);
        System.out.println("x = "+x);
}  
}

Main.java

package ktpmk12b-ictu;

/**
 * @author HARD-Code
 */
public class Main {

    public static void main(String[] args) {
      
        HePtB1 pt1 = new HePtB1();
        pt1.Input();
        if (!THUATTOAN.checkPTVN(pt1))   {
            System.out.println("__TB: PT VÔ NGHIÊM__");
        } else {
            System.out.println("-----NGHIEM THEO PP THẾ-------");
            pt1.PpThe();
            Double D[] = THUATTOAN.DinhThuc(pt1);
            System.out.println("----NGHIEM THEO ĐỊNH THỨC-----");
            System.out.println("Phuong trinh co nghiem la:");
             System.out.println("y= " + D[2] / D[0]);
            System.out.println("x= " + D[1] / D[0]);
           
        }
    }

}

THUATTOAN.java

package ktpmk12b-ictu;

/**
 *
 * @author HARD-Code
 */
public class THUATTOAN {
    /**
     * @param pt:(ax+b+c=0) => pt.a1   pt.b1    -pt.c1   
     * Return:  D[0] = D        a1b2  - a2b1
     *          D[1]= Dx        c1.b2 - b1.c2
     *          D[2]= Dy        a1.c2 - c1. a2
     */
    public static Double[] DinhThuc(HePtB1 pt) {
        Double D[] = new Double[3];
        D[0] = (pt.a1 * pt.b2) - (pt.a2 * pt.b1);
        D[1] = ((-(pt.c1)) * pt.b2) - (pt.b1 * (-(pt.c2)));
        D[2] = (pt.a1 * (-(pt.c2))) - (pt.a2 * (-(pt.c1)));
        return D;
    }

    public static boolean checkPTVN(HePtB1 _pt) {
        boolean check = true;
        if (((_pt.a1 / _pt.a2) == (_pt.b1 / _pt.b2)) && ((_pt.c1 / _pt.c2) == (_pt.b1 / _pt.b2))) 
            check = false;
        if ((_pt.a1 ==0 && _pt.a2==0 )  || (_pt.a2 ==0 &&  _pt.b2 ==0))  check =false;
        double c = THUATTOAN.DinhThuc(_pt)[0];
        if (c==0) check=false;
        return check;
    }
}