Question

Java Program

1. Write a class that reads in a group of test scores (positive integers from 1 to 100) from the keyboard. The main method of the class calls a few other methods to calculate the average of all the scores as well as the highest and lowest score. The number of scores is undetermined but there will be no more than 50. A negative value is used to end the input loop.

import java.util.Scanner;
public class GradeStat
{
final static int MAXGRADES = 50; // maximum # of grades
public static void main (String[] args) {
int[] gradeArray = new int[MAXGRADES];
int pos = 0; // Index to the array

double avgOfGrades; // contains the average of grades
int highestGrade; // contains the highest grade
int lowestGrade; // contains the lowest grade
int sizeOfArray; // the size of the used array

// input grades Scanner scan = new Scanner ( System.in );
System.out.println("Please input a grade from 1 to 100, a negative number to exit");
gradeArray[pos] = scan.nextInt();

while (gradeArray[pos] >=1) {
pos++; // increment subscript
System.out.println("Please input a grade from 1 to 100");
gradeArray[pos] = scan.nextInt();
}

sizeOfArray = pos + 1; // The actual number of elements used in the array

// call the Average method to calculate the average of gradeArray
avgOfGrades = ________________________________________;

System.out.println("The average of all the grades is “+ avgOfGrades);

// call the Highest method to calculate the highest score of gradeArray
highestGrade = ________________________________________;
System.out.println("The highest grade is " + highestGrade);

// call the Lowest method to calculate the lowest score of gradeArray
lowestGrade = _________________________________________;
System.out.println("The lowest grade is " + lowestGrade);
}

// Fill in the code to determine average grade
public static double Average(int [] array, int size)
{
}

// Fill in the code to determine highest grade
public static int Highest (int [] array, int size)
{
}

// Fill in the code to determine lowest grade
public static int Lowest (int [] array, int size)
{
}
}

2. Complete the following program that defines class Square. It has one data field called side which keeps the length of the side of a square. The class has the following methods: 1) setSide(double si), a void method that receives “si” as a parameter and sets this value to side; 2) getArea(), a method that returns the area of a square. 3) a default constructor method that sets data member side to 0; 3) a constructor that takes the “si” as a parameter and sets this value to data member side.

import java.util.Scanner;
public class Square
{
//define the data member here

// implement all the methods here

public static void main(String[] args)

{

double s;

// create a keyboard object Scanner kbd=________________________________;
System.println(“Please input the side of a square”);
// read in the value for rad from keyboard
s =_______________________________________;
// create an object of Square using the default constructor
Square aSquare = _______________________;
// create an object of Square with 2 as its side value
Square bSquare = _______________________;
__________________________________; // display areae of aSquare
__________________________________; // Sets the side of aSquare to the value of s
__________________________________; // display areae of aSquare

}

}

Answer 1

Answer 1:

import java.util.Scanner;

public class GradeStat {
   final static int MAXGRADES = 50; // maximum # of grades

   public static void main(String[] args) {
       int[] gradeArray = new int[MAXGRADES];
       int pos = 0; // Index to the array
       Scanner scan = new Scanner(System.in);
       double avgOfGrades; // contains the average of grades
       int highestGrade; // contains the highest grade
       int lowestGrade; // contains the lowest grade
       int sizeOfArray; // the size of the used array

       // input grades Scanner scan = new Scanner ( System.in );
       System.out.println("Please input a grade from 1 to 100, a negative number to exit");
       gradeArray[pos] = scan.nextInt();

       while (gradeArray[pos] >= 1) {
           pos++; // increment subscript
           System.out.println("Please input a grade from 1 to 100");
           gradeArray[pos] = scan.nextInt();
       }

       sizeOfArray = pos + 1; // The actual number of elements used in the
                               // array

       // call the Average method to calculate the average of gradeArray
       avgOfGrades = Average(gradeArray, pos);

       System.out.println("The average of all the grades is " + avgOfGrades);

       // call the Highest method to calculate the highest score of gradeArray
       highestGrade = Highest(gradeArray, pos);
       System.out.println("The highest grade is " + highestGrade);

       // call the Lowest method to calculate the lowest score of gradeArray
       lowestGrade = Lowest(gradeArray, pos);
       System.out.println("The lowest grade is " + lowestGrade);
   }

   // Fill in the code to determine average grade
   public static double Average(int[] array, int size) {
       double sum = 0;
       for (int i = 0; i < size; i++)
           sum += array[i];
       return sum / size;
   }

   // Fill in the code to determine highest grade
   public static int Highest(int[] array, int size) {
       int max = array[0];
       for (int i = 1; i < size; i++)
           if (array[i] > max)
               max = array[i];
       return max;
   }

   // Fill in the code to determine lowest grade
   public static int Lowest(int[] array, int size) {
       int min = array[0];
       for (int i = 1; i < size; i++)
           if (array[i] < min)
               min = array[i];
       return min;
   }
}

Answer 2:

import java.util.Scanner;

public class Square {
   private double side;

   public Square() {
       side = 0;
   }

   public Square(double s) {
       side = s;
   }

   public double getSide() {
       return side;
   }

   private void setSide(double aS) {
       side = aS;
   }

   private double getArea() {
       return side * side;
   }

   // define the data member here

   // implement all the methods here

   public static void main(String[] args)

   {

       double s;
       Scanner sc = new Scanner(System.in);
       // create a keyboard object Scanner
       System.out.println("Please input the side of a square");
       // read in the value for rad from keyboard
       s = sc.nextDouble();
       // create an object of Square using the default constructor
       Square aSquare = new Square();
       // create an object of Square with 2 as its side value
       Square bSquare = new Square(2);
       System.out.println("Area : " + aSquare.getArea());
       aSquare.setSide(s);
       System.out.println("Area : " + aSquare.getArea());

   }

}