Question

Language: Java

30 pts. ) - This assignment revisits the student parsing program from earlier in the quarter, but challenges you to restructure the component pieces of the program to create a cleaner, more succinct Main(). You will generate a Student class of object and load an Array List

with student objects, then report the contents of that Array List. To do so, you must

perform the following:

A)(10 /30 pts.)-

Generate a class file “myStudent.java” (which will generate myStudent.class upon compile).

myStudent.

java will have the following public methods:

1 ) readData(String fileName)-Reads a .txt file ‘students.txt’

2 ) list(String gender) - List of students whose gender is ‘gender’

3) ageAvg (String gender) - Print the average age (one digit after the decimal point)

of students whose gender is gender’

4) ageBetween (String gender, int min, int max) - Generates a list of students whose

gender is ‘gender’ and age is greater than or equal to ‘min’ and less than ‘max’.

B) (10 /30 pts.) - Once your myStudent.class is functional, generate a file “Assg07_Classes.java”. Assg07_Classes.java should contain only a Main()

method that performs the following:

1 ) Instantiate a new object of the myStudent() class.

2 ) Calls the new object and instructs it to use its .readData() method, passing an argument of a file name.

3 ) Calls the new object and instructs it to use its list() method, passing an argument of a gender.

4 ) Print the result of a call to the new object’s. ageAvg() method, passing an argument of a gender.

5) Call the new object and instruct it to use its .age Between() method, passing an argument of

a gender, a min age and max age

C) (5 /30 pts.) - The main() method of Assg07_Classes.java may not contain more than

5 lines of code.

1 ) This total does not include comments and documentation

2) This total does not include statements mentioned at the above section

B) 3) ~ 5).

3)

This total does not include optional criteria or formatting improvements to your output..

Contents of student.txt:

John m 18

William m 22

Susan f 21

Jack m 19

Jennifer f 18

Sophia f 21

Emma f 19

Olivia f 26

Ava f 23

Chloe f 17

Rachael f 22

Mia f 18

Isabella f 29

Zoe f 17

Lily f 20

Answer 1

As the instance variable in myStudent clas is a ArrayList of Students I added Student.java also

Student.java

public class Student {

private String name;

private String gender;

private int age;

//constructor

public Student(String name, String gender, int age)

{

this.name = name;

this.gender = gender;

this.age = age;

}

//setters

//method that sets the name

public void setName(String name)

{

this.name = name;

}

//method that sets the gender

public void setGender(String gender)

{

this.gender = gender;

}

//method that sets the age

public void setAge(int age)

{

this.age = age;

}

//getters

//method that returns the name

public String getName()

{

return this.name;

}

//method that return the gender

public String getGender()

{

return this.gender;

}

//method that returns the age

public int getAge()

{

return this.age;

}

//method that displays the details of a student

public void display()

{

System.out.println(String.format("%-15s %-5s %d" , getName(), getGender(), getAge()));

}

}

myStudent.java

import java.io.BufferedReader;

import java.io.FileReader;

import java.util.ArrayList;

public class myStudent {

//member variable

private ArrayList<Student> students = new ArrayList<>();

//method that read the student details from a file

public void readData(String fileName)

{

try

{

//open the file

FileReader fr = new FileReader(fileName);

BufferedReader br = new BufferedReader(fr);

String line;

//run a loop until end of file is reached

while((line = br.readLine())!=null)

{

//for each line in the file, split the line based on space

String[] splittedValues = line.split(" ");

//create a Student object with the details and add it to array list

Student s = new Student(splittedValues[0], splittedValues[1], Integer.parseInt(splittedValues[2]));

students.add(s);

}

br.close();

}

//display error message if exception raised

catch(Exception ex)

{

System.out.println("Error in reading the file.");

}

}

//method that generates a list of students of specific gender

public void list(String gender)

{

System.out.println("Students with gender " + gender + " are: ");

//iterate through each student in the list

for(int i = 0; i < students.size(); i++)

{

//if the gender matches, display it

if(students.get(i).getGender().equals(gender))

students.get(i).display();

}

}

//method that prints the average age of students with specific gender

public void ageAvg(String gender)

{

int sum = 0, count = 0;

//iterate through each student in the list

for(int i = 0; i < students.size(); i++)

{

//if the gender matches

if(students.get(i).getGender().equals(gender))

{

//add the age to sum

sum = sum + students.get(i).getAge();

count++;

}

}

//compute and display the average age

double avg = (double)(sum)/(double)(count);

System.out.printf("\nThe average age of students with gender %s is %.1f\n", gender, avg);

}

//method that generates a list of students of specific gender and age between min and max

public void ageBetween(String gender, int min, int max)

{

System.out.println("\nStudents with gender " + gender + " and age between " + min + " and " + max + " are: ");

//iterate through each student in the list

for(int i = 0; i < students.size(); i++)

{

//if the gender matches

if(students.get(i).getGender().equals(gender))

{

//check if student age is between min and max, if yes display it

if(students.get(i).getAge() >= min && students.get(i).getAge() <= max)

students.get(i).display();

}

}

}

}

Assg07_Classes.java

public class Assg07_Classes {

public static void main(String[] args) {

//Instantiate a new object of the myStudent() class.

myStudent s = new myStudent();

//Calls the new object and instructs it to use its .readData() method, passing an argument of a file name.

s.readData("students.txt");

//Calls the new object and instructs it to use its list() method, passing an argument of a gender

s.list("f");

//Print the result of a call to the new object’s. ageAvg() method, passing an argument of a gender

s.ageAvg("f");

//Call the new object and instruct it to use its .age Between() method, passing an argument of a gender, a min age and max age

s.ageBetween("f", 20, 25);

}

}

Output:

Let me know if you have any concerns with the above solution.