Chapter 3 Exercise 33, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*3.33 (Financial: compare costs) Suppose you shop for rice in two different packages. You would like to write a program to compare the cost. The program prompts the user to enter the weight and price of the each package and displays the one with the better price. Here is a sample run:

Enter weight and price for package 1: 50 24.59
Enter weight and price for package 2: 25 11.99
Package 2 has a better price. 

Enter weight and price for package 1: 50 25
Enter weight and price for package 2: 25 12.5
Two packages have the same price. 

import java.util.Scanner;
 
public class ProgrammingEx3_33 {
 public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
  System.out.println("Enter weight and price for package 1:");
  double w1 = input.nextDouble();
  double p1 = input.nextDouble();
  System.out.println("Enter weight and price for package 2:");
  double w2 = input.nextDouble();
  double p2 = input.nextDouble();
  double r = w2 / p2 - w1 / p1;
  String s = "";
 
  if (r < 0.0000001) { // comparing double to zero is not reliable, using
        // minimum threshold instead
   System.out.println("Two packages have the same price.");
   System.exit(0);
  }
 
  if (r > 0) {
   s = "Pakage 2";
  } else {
   s = "Pakage 1";
  }
 
  System.out.println(s + " has better price.");
 
 }
 
}