Question

Java...Stay on the Screen! Animation in video games is just like animation in movies – it’s drawn image by image (called “frames”). Before the game can draw a frame, it needs to update the position of the objects based on their velocities (among other things). To do that is relatively simple: add the velocity to the position of the object each frame. For this program, imagine we want to track an object and detect if it goes off the left or right side of the screen (that is, it’s X position is less than 0 and greater than the width of the screen, say, 100). Write a program that asks the user for the starting X and Y position of the object as well as the starting X and Y velocity, then prints out its position each frame until the object moves off of the screen. Design Java(source code) for this program.

Sample run 1: Enter the starting X position: 50

Enter the starting Y position: 50

Enter the starting X velocity: 4.7

Enter the starting Y velocity: 2

X:50 Y:50

X:54.7 Y:52

X:59.4 Y:54

X:64.1 Y:56

X:68.8 Y:58

X:73.5 Y:60

X:78.2 Y:62

X:82.9 Y:64

X:87.6 Y:66

X:92.3 Y:68

X:97 Y:70

X:101.7 Y:72

Sample run 2: Enter the starting X position: 20

Enter the starting Y position: 45

Enter the starting X velocity: -3.7

Enter the starting Y velocity: 11.2

X:20 Y:45

X:16.3 Y:56.2

X:12.6 Y:67.4

X:8.9 Y:78.6

X:5.2 Y:89.8

X:1.5 Y:101

X:-2.2 Y:112.2  

Answer 1

ScreenPositionXY.java :

//import package
import java.util.*;
//java class
public class ScreenPositionXY {
   public static void main(String[] args) {
       //creating object of Scanner class
       Scanner sc=new Scanner(System.in);
       //starting X position
       System.out.print("Enter the starting X position: ");
       double startingX=sc.nextDouble();//reading X
       //starting Y position
       System.out.print("Enter the starting Y position: ");
       double startingY=sc.nextDouble();//reading Y
       //starting X velocity
       System.out.print("Enter the starting X velocity: ");
       double vcX=sc.nextDouble();//X velocity
       //starting y velocity
       System.out.print("Enter the starting Y velocity: ");
       double vcY=sc.nextDouble();//reading Y velocity
       //using while loop
       while(startingX>0 && startingX<=100)
       {
           //print X position
           System.out.printf("X:%.1f",startingX);
           //print X position
           System.out.printf(" Y:%.1f\n",startingY);
           //increment startingX by vcX
           startingX=startingX+vcX;
           //increment startingY by vcY
           startingY=startingY+vcY;
       }
       System.out.printf("X:%.1f",startingX);//print X position
       System.out.printf(" Y:%.1f",startingY);//print Y position
          
   }

   }
=========================

Output 1:

Console X Debug Shell 4 x 8 E F G H E • F <terminated> Screen Position XY [Java Application] C:\Program FilesVava\jdk1.8.0_181\bin\javaw.exe (03-Oct-2019, Enter the starting X position: 50 Enter the starting Y position: 50 Enter the starting X velocity: 4.7 Enter the starting Y velocity: 2 X:50.0 Y:50.0 X:54.7 Y:52.0 X:59.4 Y:54.0 X:64.1 Y:56.0 X:68.8 Y:58.0 X:73.5 Y:60.0 X:78.2 Y:62.0 X:82.9 Y:64.0 X:87.6 Y:66.0 X:92.3 Y:68.0 X:97.0 Y:70.0 X: 101.7 Y:72.0

Output 2:

Console X Debug Shell | x | = b = = = = = = = <terminated> ScreenPositionXY [Java Application] C:\Program Files Vava\jdk1.8.0_181\bin\javaw.exe (03-Oct-2019, Enter the starting X position: 20 Enter the starting Y position: 45 Enter the starting X velocity: -3.7 Enter the starting Y velocity: 11.2 K:20.0 Y:45.0 X:16.3 Y:56.2 X:12.6 Y:67.4 X:8.9 Y:78.6 X:5.2 Y:89.8 X:1.5 Y: 101.0 X:-2.2 Y: 112.2