1. Define a class Student which extends Person defined in class. It adds the att

Question

1. Define a class Student which extends Person defined in class. It adds the attributes Int Testl, test2, test3 Double average String grade Define a constructor which takes all the attributes of person and uses a default value of 0 for the test scores, "unknown" for grade and 0 for aversge. It has methods computeaverage0 and calculategrade(). The grades are based on the average, with above 92 an A, 85 to 92 a B, 70 to 85 a C, 60 to 70 a D etc. Grades only has a getter. All other attributes have a setter and a getter. 2. Write an application that uses an array of type student of size 20. The program prompts the user for the name of a text file and reads from the file to start the program. Then it gives a menu. 1. Enter a student 2. List the names of all the students 3. Enter the test scores for a student specified by name 4. Find the grade of a student s. Quit 3. When the user quits the students are written to the text

Explanation / Answer

Note: Plz let me know if u face any problemn whiel running it..so that I will rectify it..thank You

testscores.txt

sachin 90 89 87
Pointing 76 89 72
Rahul 67 56 45
Raman 67 78 91
John 78 34 56
Williams 78 89 87

______________

Person.java

public class Person {
private String name;

public Person() {

}
public Person(String name) {
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

____________________

Student.java

public class Student extends Person {
private int test1;
private int test2;
private int test3;
private String grade;
private double average;

public Student() {
this.test1 = 0;
this.test2 = 0;
this.test3 = 0;
this.grade = "Unkown";
this.average = 0;
}

public Student(String name, int test1, int test2, int test3) {
super(name);
this.test1 = test1;
this.test2 = test2;
this.test3 = test3;
this.grade = grade;
this.average = average;
}

public double computeAverage() {
this.average = (test1 + test2 + test3) / 3.0;
return average;
}
public String calculateGrade() {

if (average > 92)
grade = "A";
else if (average > 85 && average <= 92)
grade = "B";
else if (average > 70 && average <= 85)
grade = "C";
else if (average > 60 && average <= 70)
grade = "D";
else if (average <= 60)
grade = "F";

this.grade = grade;
return grade;
}

public int getTest1() {
return test1;
}

public void setTest1(int test1) {
this.test1 = test1;
}

public int getTest2() {
return test2;
}

public void setTest2(int test2) {
this.test2 = test2;
}

public int getTest3() {
return test3;
}

public void setTest3(int test3) {
this.test3 = test3;
}

public String getGrade() {
return grade;
}

public void setGrade(String grade) {
this.grade = grade;
}

public double getAverage() {
return average;
}

public void setAverage(double average) {
this.average = average;
}

}

______________________

Test.java

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.PrintWriter;

import java.text.DecimalFormat;

import java.util.Scanner;

public class Test {

public static void main(String[] args) throws FileNotFoundException {

String filename,name;

int tst1,tst2,tst3;

int i=0;

Student starr[]=new Student[20];

Scanner s1 = null;

Student st1;

FileOutputStream fout = null;

PrintWriter writer = null;

/*

* Creating an Scanner class object which is used to get the inputs

* entered by the user

*/

Scanner sc = new Scanner(System.in);

System.out.print("Enter the name of the text file :");

filename=sc.next();

try {

s1=new Scanner(new File(filename));

while(s1.hasNext())

{

name=s1.next();

tst1=s1.nextInt();

tst2=s1.nextInt();

tst3=s1.nextInt();

st1=new Student(name, tst1, tst2, tst3);

starr[i]=st1;

i++;

}

} catch (FileNotFoundException e) {

e.printStackTrace();

}

s1.close();

int choice ;

while(true)

{

System.out.println(":: Menu ::");

System.out.println("1.Enter a Student");

System.out.println("2.List the names of all students");

System.out.println("3.Enter the test scores for a student speciad by name");

System.out.println("4.Find the grade of the Student");

System.out.println("5.Quit");

System.out.print("Enter Choice :");

choice=sc.nextInt();

switch(choice)

{

case 1:{

System.out.println("Enter the name of the Student :");

name=sc.next();

if(i<20)

{

System.out.println("Enter score in test#1 :");

tst1=sc.nextInt();

System.out.println("Enter score in test#2 :");

tst2=sc.nextInt();

System.out.println("Enter score in test#3 :");

tst3=sc.nextInt();

st1=new Student(name, tst1, tst2, tst3);

starr[i]=st1;

i++;

}

else

{

System.out.println("** Student Array is full **");

}

continue;

}

case 2:{

System.out.println("List of all student names are :");

for(int k=0;k<i;k++)

{

System.out.println(starr[k].getName());

}

continue;

}

case 3:{

int index=0;

System.out.print("Enter student name:");

name=sc.next();

while(index<i)

{

if(name.equalsIgnoreCase(starr[index].getName()))

{

System.out.println("Enter score in test#1 :");

tst1=sc.nextInt();

System.out.println("Enter score in test#2 :");

tst2=sc.nextInt();

System.out.println("Enter score in test#3 :");

tst3=sc.nextInt();

starr[index].setTest1(tst1);

starr[index].setTest2(tst2);

starr[index].setTest3(tst3);

break;

}

index++;

}

continue;

}

case 4:{

int index=0;

System.out.print("Enter the name of the Stduent :");

name=sc.next();

while(index<i)

{

if(name.equalsIgnoreCase(starr[index].getName()))

{

System.out.println("The Grade of the Stduent is :"+starr[index].calculateGrade());

break;

}

index++;

}

continue;

}

case 5:{

/* Instantiate a FileOutputStream object for file "dataOutput.txt"

* Do not specify a path .Your file will be created in the project folder

*/

fout = new FileOutputStream("dataOutput.txt");

/*

* Instantiate a PrintWriter Object for writing data to your FileOutputStream

*/

writer = new PrintWriter(fout);

DecimalFormat df=new DecimalFormat("#.##");

for(int h=0;h<i;h++)

{

writer.write(starr[h].getName()+" ");

writer.write(starr[h].getTest1()+" ");

writer.write(starr[h].getTest2()+" ");

writer.write(starr[h].getTest3()+" ");

writer.write(df.format(starr[h].computeAverage())+" ");

writer.write(starr[h].calculateGrade()+" ");

writer.println();

  

  

}

System.out.println("** Data Written to outfile **");

System.out.println("** Program Exit **");

writer.close();

break;

}

default:{

System.out.println("** Invalid Choice **");

continue;

}

}

break;

}

}

}

______________________

Output:

Enter the name of the text file :testscores.txt
:: Menu ::
1.Enter a Student
2.List the names of all students
3.Enter the test scores for a student speciad by name
4.Find the grade of the Student
5.Quit
Enter Choice :5
** Data Written to outfile **
** Program Exit **

_______________________

dataOutput.txt

sachin 90 89 87 88.67 B
Pointing 76 89 72 79 C
Rahul 67 56 45 56 F
Raman 67 78 91 78.67 C
John 78 34 56 56 F
Williams 78 89 87 84.67 C

_____________Could you rate me well.Plz .Thank You

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