Solutions to the Try It Out Exercises in Beginning Programming with Java For Dummies, 6th Edition
by Barry Burd

Chapter 13: Programming with Objects and Classes

In this chapter:

• What's your BMI?
• A bit of macroeconomics
• Nothing in particular

What's your BMI?

public class Person {
    double weight;
    double height;
}


import java.util.Scanner;

public class FindBmi {

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);

        Person person1 = new Person();
        System.out.println("Person 1");
        System.out.print("Weight? ");
        person1.weight = keyboard.nextDouble();
        System.out.print("Height? ");
        person1.height = keyboard.nextDouble();
        System.out.println();
        
        System.out.println("Person 2");
        Person person2 = new Person();
        System.out.print("Weight? ");
        person2.weight = keyboard.nextDouble();
        System.out.print("Height? ");
        person2.height = keyboard.nextDouble();
        System.out.println();
        
        System.out.println("Person 3");
        Person person3 = new Person();
        System.out.print("Weight? ");
        person3.weight = keyboard.nextDouble();
        System.out.print("Height? ");
        person3.height = keyboard.nextDouble();
        System.out.println();
        
        System.out.print("Person 1's BMI: ");
        System.out.println(person1.weight / (person1.height * person1.height));
        
        System.out.print("Person 2's BMI: ");
        System.out.println(person2.weight / (person2.height * person2.height));

        System.out.print("Person 3's BMI: ");
        System.out.println(person3.weight / (person3.height * person3.height));

        keyboard.close();
    }

}

A bit of macroeconomics

public class Country {
    double debt;
    double gdp;
}


import java.util.Scanner;

public class DebtToGdbRatio {

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);

        Country country1 = new Country();
        System.out.println("Country 1");
        System.out.print("Debt? ");
        country1.debt = keyboard.nextDouble();
        System.out.print("GDP? ");
        country1.gdp = keyboard.nextDouble();
        System.out.println();
        
        System.out.println("Country 2");
        Country country2 = new Country();
        System.out.print("Debt? ");
        country2.debt = keyboard.nextDouble();
        System.out.print("GDP? ");
        country2.gdp = keyboard.nextDouble();
        System.out.println();
        
        System.out.println("Country 3");
        Country country3 = new Country();
        System.out.print("Debt? ");
        country3.debt = keyboard.nextDouble();
        System.out.print("GDP? ");
        country3.gdp = keyboard.nextDouble();
        System.out.println();
        
        System.out.print("Acceptable debt-to-GDP ratio? ");
        double threshold = keyboard.nextDouble();
        System.out.println();
        
        double ratio;
        
        System.out.print("Country 1's ratio is ");
        ratio = country1.debt / country1.gdp; 
        System.out.println(ratio);
        if (ratio <= threshold) {
            System.out.println("That's acceptable");
        } else {
            System.out.println("That's not acceptable");
        }
        System.out.println();
        
        System.out.print("Country 2's ratio is ");
        ratio = country2.debt / country2.gdp; 
        System.out.println(ratio);
        if (ratio <= threshold) {
            System.out.println("That's acceptable");
        } else {
            System.out.println("That's not acceptable");
        }
        System.out.println();

        System.out.print("Country 3's ratio is ");
        ratio = country3.debt / country3.gdp; 
        System.out.println(ratio);
        if (ratio <= threshold) {
            System.out.println("That's acceptable");
        } else {
            System.out.println("That's not acceptable");
        }
        System.out.println();
        
        keyboard.close();
    }

}

Nothing in particular

public class Thing {
    int value1;
    int value2;
}


import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);

        Thing thing1 = new Thing();
        System.out.println("Thing 1");
        System.out.print("value1? ");
        thing1.value1 = keyboard.nextInt();
        System.out.print("value2? ");
        thing1.value2 = keyboard.nextInt();
        System.out.println();
        
        System.out.println("Thing 2");
        Thing thing2 = new Thing();
        System.out.print("value1? ");
        thing2.value1 = keyboard.nextInt();
        System.out.print("value2? ");
        thing2.value2 = keyboard.nextInt();
        System.out.println();
        
        System.out.println("Thing 3");
        Thing thing3 = new Thing();
        System.out.print("value1? ");
        thing3.value1 = keyboard.nextInt();
        System.out.print("value2? ");
        thing3.value2 = keyboard.nextInt();
        System.out.println();
        
        System.out.print("Thing 1 has values ");
        System.out.print(thing1.value1);
        System.out.print(" and ");
        System.out.print(thing1.value2);
        System.out.println(".");
        
        System.out.print("Thing 2 has values ");
        System.out.print(thing2.value1);
        System.out.print(" and ");
        System.out.print(thing2.value2);
        System.out.println(".");
        
        System.out.print("Thing 3 has values ");
        System.out.print(thing3.value1);
        System.out.print(" and ");
        System.out.print(thing3.value2);
        System.out.println(".");
       

        keyboard.close();
    }

}