SELECTIONS - Introduction to Java Programming: Comprehensive Version - page 114

Write a program that prompts the user to enter four points and displays the inter-
secting point. Here are sample runs:

( x 2, y 2) ( x 2, y 2) ( x 3, y 3)

( x 2, y 2)

( x 3, y 3)

( x 3, y 3)

( x 4, y 4)

( x 1, y 1) ( x 1, y 1) ( x 4, y 4) ( x 1, y 1) ( x 4, y 4)

(a) (b) (c)

F IGURE 3.8

Two lines intersect in (a and b) and two lines are parallel in (c).

Enter x1, y1, x2, y2, x3, y3, x4, y4: 2 2 5 -1.0 4.0 2.0 -1.0 -2.0
The intersecting point is at (2.88889, 1.1111)

Enter x1, y1, x2, y2, x3, y3, x4, y4: 2 2 7 6.0 4.0 2.0 -1.0 -2.0
The two lines are parallel

3.26

( Use the && , || and ^ operators ) Write a program that prompts the user to enter
an integer and determines whether it is divisible by 5 and 6, whether it is divisible
by 5 or 6, and whether it is divisible by 5 or 6, but not both. Here is a sample run
of this program:

Enter an integer: 10
Is 10 divisible by 5 and 6? false
Is 10 divisible by 5 or 6? true
Is 10 divisible by 5 or 6, but not both? true

**3.27

( Geometry: points in triangle? ) Suppose a right triangle is placed in a plane as
shown below. The right-angle point is placed at (0, 0), and the other two points
are placed at (200, 0), and (0, 100). Write a program that prompts the user to enter
a point with x - and y -coordinates and determines whether the point is inside the
triangle. Here are the sample runs:

(0, 100)

p 2

p 1

(0, 0) (200, 0)

Enter a point's x- and y-coordinates: 100.5 25.5
The point is in the triangle