NOTE: Solutions to the problems are meant to be used as a learning aid. Simply copying and pasting the material will not result in your learning how to program.

Problem 1 Solution - So that you may learn by this first example the code has been heavily commented.

Class EnterNum:

import java.util.*; // import the util library so we can create a Scanner object
public class EnterNum
{
    Scanner in = new Scanner(System.in);
    private int enteredNum; // declare a field variable named enteredNum

    // constructor that sets the field variable named enteredNum to 0
    public EnterNum()
    {
        enteredNum = 0;
    }

    // method that asks for an integer to be entered and then
    // the value entered is placed in the field variable named enteredNum
    public void setEnteredNum()
    {
        System.out.print("Enter an integer: ");
        enteredNum=in.nextInt();
    }
   
    // a method that is used to get the current value of the field variable named enteredNum
    public int getEnteredNum()
    {
        return enteredNum; // send the value of enteredNum to where it is being requested
    }
}

 

Class Multiply:

public class Multiply
{
    
    private int product; // declare a field variable named product

    // constructor that sets the field variable named product to 0
    public Multiply()
    {
        product=0;
    }

    // this method receives two integer values passed as parameters
    // the values are multiplied together and then the value is
    // placed in the field variable named product
    public void setProduct(int n1, int n2)
    {
        product = n1*n2;
    }
    
    // this method sends the value in the field variable named product to the place that requested it
    public int getProduct()
    {   
       return product;
    }
}

Class Add:

public class Add
{
    private int sum; // declare a field variable named sum

    // constructor that sets the field variable named sum to 0
    public Add()
    {
        sum=0;
    }

    // this method receives two integer values passed as parameters
    // the values are added together and then the value is
    // placed in the field variable named sum
    public void setSum(int n1, int n2)
    {
        sum = n1+n2;
    }
    
    // this method sends the value in the field variable named sum to the place that requested it
    public int getSum()
    {   
       return sum;
    }
}

Class Problem1:

public class Problem1
{

  static EnterNum numGetter = new EnterNum(); // create an instance of the EnterNum Class named numGetter
  static Multiply multiplier = new Multiply(); // create an instance of the Multiply Class named multiplier
  static Add adder = new Add(); // create an instance of the Add Class named adder

  // this is the main method  
  public static void main (String[] args)
    {
        int num1,num2,theSum,theProduct; // declare the local variable that will be used
        numGetter.setEnteredNum(); //the numGetter object executes its askForNumber() method
        num1=numGetter.getEnteredNum();//the numGetter object executes its getNumber() method and places the value in num1
        numGetter.setEnteredNum(); //the numGetter object executes its askForNumber() method
        num2=numGetter.getEnteredNum();//the numGetter object execute its getNumber() method and places the value in num2
        multiplier.setProduct(num1,num2);//the multiplier object executes its multiplyNums() method sending along the values in num1 & num2
        theProduct=multiplier.getProduct();//the multiplier object executes its getProduct() method and places the result in theProduct
        adder.setSum(num1,num2);//the adder object executes its addNums() method sending along the values in num1 & num2
        theSum=adder.getSum();//the adder object executes its getSum() method and places the result in the variable theSum
        System.out.println(num1+" * "+num2+" = "+theProduct);// display the output on the computer screen
        System.out.println(num1+" + "+num2+" = "+theSum);// display the output on the computer screen
    }
}

Class GetUserName:

import java.util.*;
public class GetUserName
{
    Scanner in = new Scanner(System.in);
    private String firstName,lastName;

    public GetUserName()
    {
        firstName = "";
        lastName = "";
    }


    public void setFirstName()
    {
       System.out.print("Enter your first name: ");
       firstName=in.next();
    }
   
     public void setLastName()
    {
       System.out.print("Enter your last name: ");
       lastName=in.next();
    }
  
    public String getFirstName()
    {
        return firstName;
    }
      
    public String getLastName()
    {
        return lastName;
    }
   
}

 

Class GetFavAnimal:

import java.util.*;
public class GetFavAnimal
{
    Scanner in = new Scanner(System.in);
    private String animal;

    public GetFavAnimal()
    {
        animal = "";
    }


    public void setAnimal()
    {
       System.out.print("Enter your favorite animal: ");
       animal=in.next();
    }
   
      
    public String getAnimal()
    {
        return animal;
    }
   
}

 

Class Problem2

public class Problem2
{

  static GetUserName user = new GetUserName();
  static GetFavAnimal fav = new GetFavAnimal();

  public static void main (String[] args)
    {
        String fName,lName,fAnimal;
        user.setFirstName();
        fName=user.getFirstName();
        user.setLastName();
        lName=user.getLastName();
        fav.setAnimal();
        fAnimal=fav.getAnimal();
        System.out.println();// print an empty line
        System.out.println("hello "+fName+". My last name is also "+lName+" and my favorite animal is also a "+fAnimal+".");
    }
}

 

EnterValues Class:

import java.util.*;
public class EnterValues
{
    Scanner in = new Scanner(System.in);
    private double height,weight;

    public EnterValues()
    {
        height=0;
        weight = 0;
    }

    
    public void setWeight()
    {
       System.out.print("Enter your weight in pounds: ");
       weight = in.nextDouble();
    }
    
    public void setHeight()
    {
       System.out.print("Enter your height in pounds: ");
       height = in.nextDouble();
    }  
    
    public double getWeight()
    {
        return weight;
    }
    
    public double getHeight()
    {
        return height;
    }
}

DivideNumbers Class:

public class DivideNumbers
{
    private double quotient;


    public DivideNumbers()
    {
        quotient = 0;
    }

    public void setQuotient(double w, double h)
    {
        quotient = w / h;
    }
   
    public double getQuotient()
    {
        return quotient;
    }
}

 

Problem3 Class:

public class Problem3
{
   static EnterValues values = new EnterValues();
   static DivideNumbers divider = new DivideNumbers();
  

     public static void main (String[] args)
    {
        double weight,height,answer;
        values.setWeight();
        values.setHeight();
        weight=values.getWeight();
        height=values.getHeight();
        divider.setQuotient(weight,height);
        answer=divider.getQuotient();
        System.out.println();
        System.out.println("You weigh "+answer+" pounds per inch!");
    }
}

 

GetDimensions Class:

import java.util.*;
public class GetDimensions
{
    Scanner in = new Scanner(System.in);  
    private int height,width,length;


    public GetDimensions()
    {
        height = 0;
        width=0;
        length=0;
    }

    public void setHeight()
    {
        System.out.print("Enter the room's height (in feet): ");
        height=in.nextInt();
    }
    
    public void setWidth()
    {
        System.out.print("Enter the room's width (in feet): ");
        width=in.nextInt();
    }   
    
    public void setLength()
    {
        System.out.print("Enter the room's length (in feet): ");
        length=in.nextInt();
    }
    
    public int getHeight()
    {
        return height;
    }
    
    public int getLength()
    {
        return length;
    }
    
    public int getWidth()
    {
        return width;
    }
}

CalcVolume Class:

public class CalcVolume
{
  
    private int volume;

    public CalcVolume()
    {
        volume = 0;
    }

    public void setVolume(int H, int W, int L)
    {
        volume = H * W * L;
    }
   
    public int getVolume()
    {
        return volume;
    }
}

 

Problem4 Class:

public class Problem4
{

    static GetDimensions dimensioner = new GetDimensions();
    static CalcVolume volumizer = new CalcVolume();


    public static void main (String[] args)
    {
       int height,width,length,volume;
      
       dimensioner.setHeight();
       dimensioner.setWidth();
       dimensioner.setLength();
       height=dimensioner.getHeight();
       width=dimensioner.getWidth();
       length=dimensioner.getLength();
       volumizer.setVolume(height,width,length);
       volume=volumizer.getVolume();
       System.out.println();
       System.out.println("The volume of the room is "+volume+" cubic feet.");
      
    }
}

 

TriangleValues Class:

import java.util.*;
public class TriangleValues
{
    Scanner in = new Scanner(System.in);
    private int base,height;

    public TriangleValues()
    {
        base = 0;
        height = 0;
    }

    public void setBase()
    {
        System.out.print("Enter the base (inches): ");
        base=in.nextInt();
    }
   
    public void setHeight()
    {
        System.out.print("Enter the height (inches): ");
        height=in.nextInt();
    }
   
    public int getHeight()
    {
        return height;
    }
  
    public int getBase()
    {
        return base;
    }   
}
 

TriangleArea Class:

public class TriangleArea
{
    private double area;


    public TriangleArea()
    {
        area = 0.0;
    }

    public void setArea(int b, int h)
    {
        area = 0.5 * b * h ;
    }
   
    public double getArea()
    {
        return area;
    }
}
 

Problem5 Class:

public class Problem5
{
    static TriangleValues triangle = new TriangleValues();
    static TriangleArea triangulator = new TriangleArea();

    public static void main (String[] args)
    {
        int base,height;
        double area;
        triangle.setBase();
        triangle.setHeight();
        base=triangle.getBase();
        height=triangle.getHeight();
        triangulator.setArea(base,height);
        area=triangulator.getArea();
        System.out.println();
        System.out.println("The triangle's area is "+area+" square inches.");
    }
}
 

EnterNumbers Class:

import java.util.*;
public class EnterNumbers
{
    Scanner in = new Scanner(System.in);
    private int num;

    public EnterNumbers()
    {
        num = 0;
    }


    public void setNum(int firstOrSecond)
    {
      if(firstOrSecond==1)
       {
         System.out.print("Enter a whole number: ");
         num=in.nextInt();
       }
      else
       {
         System.out.print("Enter another whole number (smaller than the first number): ");
         num=in.nextInt();
       }    
    }
   
    public int getNum()
    {
        return num;
    }
}
 

VerifyInput Class:

public class VerifyInput
{

    public boolean compareNums(int n1, int n2)
    {
        if(n2<n1)
        return true;
        else
        return false;
    }
}
 

WholeDivider Class:

public class WholeDivider
{
    // instance variables - replace the example below with your own
    private int whole,remainder;

    public WholeDivider()
    {
        whole=0;
        remainder=0;
    }


    public void setWhole(int n1, int n2)
    {
        whole=n1/n2;
    }
   
    public void setRemainder(int n1, int n2)
    {
        remainder=n1%n2;
    }
   
    public int getWhole()
    {
        return whole;
    }

    public int getRemainder()
    {
        return remainder;
    }
}
 

Problem6 Class:

public class Problem6
{
    static EnterNumbers enterNum = new EnterNumbers();
    static WholeDivider divider = new WholeDivider();
    static VerifyInput verifier = new VerifyInput();
   
    public static void main (String[] args)
    {
        int first,second,wholePart,remainderPart;
       
        enterNum.setNum(1);
        first=enterNum.getNum();
        do{
        enterNum.setNum(2);
        second=enterNum.getNum();
        if(verifier.compareNums(first,second)==false)
        System.out.println("Invalid entry. Second number must be less than the first.");
        }while(verifier.compareNums(first,second)==false);
        divider.setWhole(first,second);
        wholePart=divider.getWhole();
        divider.setRemainder(first,second);
        remainderPart=divider.getRemainder();       
        System.out.println();
        System.out.println(first+" divided by "+second+" is "+wholePart+" with a remainder of "+remainderPart);
       
    }
}
 

CalcBoxes Class:

public class CalcBoxes
{
    // instance variables - replace the example below with your own
    private int largeSize,smallSize,largeBoxes,smallBoxes;


    public CalcBoxes()
    {
        largeSize=4;
        smallSize=1;
        largeBoxes=0;
        smallBoxes=0;
    }

    public void setLargeBoxes(int potsOrdered)
    {
        largeBoxes=potsOrdered/largeSize;
    }
   
    public void setSmallBoxes(int potsOrdered)
    {
        smallBoxes=potsOrdered%largeSize/smallSize;
    }
   
    public int getLargeBoxes()
    {
        return largeBoxes;
    }
   
    public int getSmallBoxes()
    {
        return smallBoxes;
    }
}
 

EnterPots Class:

import java.util.*;

public class EnterPots
{
    Scanner in = new Scanner(System.in);
    private int pots;


    public EnterPots()
    {
        pots = 0;
    }


    public void setPots()
    {
        System.out.print("Enter the number of flower pots ordered: ");
        pots=in.nextInt();
    }
   
    public int getPots()
    {
        return pots;
    }
}
 

Problem7 Class:

public class Problem7
{
    static EnterPots potsOrder = new EnterPots();
    static CalcBoxes calculate = new CalcBoxes();


    public static void main (String[] args)
    {
        int numPotsOrdered,large,small;
        potsOrder.setPots();
        numPotsOrdered=potsOrder.getPots();
        calculate.setLargeBoxes(numPotsOrdered);
        large=calculate.getLargeBoxes();
        calculate.setSmallBoxes(numPotsOrdered);
        small=calculate.getSmallBoxes();
        System.out.println("You will need "+large+" large boxes and "+small+" small boxes.");
    }
}
 

EnterPots Class:

import java.util.*;

public class EnterPots
{
    Scanner in = new Scanner(System.in);
    private int pots;


    public EnterPots()
    {
        pots = 0;
    }


    public void setPots()
    {
        System.out.print("Enter the number of flower pots ordered: ");
        pots=in.nextInt();
    }
   
    public int getPots()
    {
        return pots;
    }
}
 

CalcBoxes Class:

public class CalcBoxes
{
    // instance variables - replace the example below with your own
    private int largeSize,mediumSize,smallSize,largeBoxes,mediumBoxes,smallBoxes;


    public CalcBoxes()
    {
        largeSize=8;
        mediumSize=4;
        smallSize=1;
        largeBoxes=0;
        mediumBoxes=0;
        smallBoxes=0;
    }

    public void setLargeBoxes(int potsOrdered)
    {
        largeBoxes=potsOrdered/largeSize;
    }
   
    public void setMediumBoxes(int potsOrdered)
    {
        mediumBoxes=potsOrdered%largeSize/mediumSize;
    }   
   
    public void setSmallBoxes(int potsOrdered)
    {
        smallBoxes=potsOrdered%largeSize%mediumSize/smallSize;
    }
   
    public int getLargeBoxes()
    {
        return largeBoxes;
    }
   
    public int getMediumBoxes()
    {
        return mediumBoxes;
    }   
   
    public int getSmallBoxes()
    {
        return smallBoxes;
    }
}
 

Problem7 Class:

public class Problem7
{
    static EnterPots potsOrder = new EnterPots();
    static CalcBoxes calculate = new CalcBoxes();


    public static void main (String[] args)
    {
        int numPotsOrdered,large,medium,small;
        potsOrder.setPots();
        numPotsOrdered=potsOrder.getPots();
        calculate.setLargeBoxes(numPotsOrdered);
        large=calculate.getLargeBoxes();
        calculate.setMediumBoxes(numPotsOrdered);
        medium=calculate.getMediumBoxes();       
        calculate.setSmallBoxes(numPotsOrdered);
        small=calculate.getSmallBoxes();
        System.out.println("You will need "+large+" large boxes and "+medium+" medium boxes and "+small+" small boxes.");
    }
}
 

RandomNumGenerator Class:

public class RandomNumGenerator
{
    private int randomNumber;

    public RandomNumGenerator()
    {
        randomNumber = 0;
    }

    public void setRandomNumber(int max, int min)
    {
        randomNumber=(int)(Math.random()*(max-min+1)+min);
    }
   
    public int getRandomNumber()
    {
        return randomNumber;
    }
}
 

Problem9 Class:

public class Problem9
{
  static RandomNumGenerator makeNum = new RandomNumGenerator();


  public static void main (String[] args)
    {
        int num1,num2,num3;
        makeNum.setRandomNumber(15,1);
        num1=makeNum.getRandomNumber();
        makeNum.setRandomNumber(20,15);
        num2=makeNum.getRandomNumber();
        makeNum.setRandomNumber(76,75);
        num3=makeNum.getRandomNumber();       
        System.out.println("The number selected from 1 to 15 is "+num1);
        System.out.println("The number selected from 15 to 20 is "+num2);
        System.out.println("The number selected from 75 to 76 is "+num3);
    }
}