Chapter 9 Exercise 12, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

9.12 (Geometry: intersecting point) Suppose two line segments intersect. The two end-points for the first line segment are (x1, y1) and (x2, y2) and for the second line segment are (x3, y3) and (x4, y4). Write a program that prompts the user to enter these four endpoints and displays the intersecting point. As discussed in Program- ming Exercise 3.25, the intersecting point can be found by solving a linear equation. Use the LinearEquation class in Programming Exercise 9.11 this is the code from 9.11

import java.util.Scanner;

public class LinearEquationTest {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("Enter value of a, b, c, d, e and f: ");

int a = sc.nextInt(); int b = sc.nextInt(); int c = sc.nextInt(); int d = sc.nextInt(); int e = sc.nextInt(); int f = sc.nextInt(); LinearEquation eqution = new LinearEquation(a, b, c, d, e, f); System.out.println("isSolavable: "+eqution.isSolavable()); System.out.println("X: "+eqution.getX()); System.out.println("Y: "+eqution.getY()); } }

/* Sample run: Enter value of a, b, c, d, e and f:

1 2 3 4 5 6 isSolavable: true X: -4.0 Y: 4.5 */ -------------

and

public class LinearEquation {

// instance variables

private int a, b, c, d, e, f;

// constructor

public LinearEquation(int a, int b, int c, int d, int e, int f) {

this.a = a; this.b = b; this.c = c; this.d = d; this.e = e; this.f = f;

}

// getters

public int getA() {

return a;

}

public int getB() {

return b;

}

public int getC() {

return c;

}

public int getD() {

return d;

}

public int getE() {

return e;

}

public int getF() {

return f;

}

// other functions

public boolean isSolavable(){

if((a*d - b*c) != 0)

return true;

else

return false;

}

public double getX(){

if(isSolavable())

return (double)(e*d - b*f)/(double)(a*d - b*c);

else

return -999;

}

public double getY(){

if(isSolavable())

return (double)(a*f - e*c)/(double)(a*d - b*c);

else

return -999;

}

}