Hello,

This program works I want to attempt to correct the output. My task is to create a program in java to enter, grades, calculate average and letter grade.

Output:

Name: GinaHarrell

ID:123

Grade1: 90

Grade2:98

Grade3: 100Average grade: 96.0

Letter grade:A,

Name: JamesStagg

ID:678

Grade1: 98

Grade2:56

Grade3: 98Average grade: 84.0

Letter grade:B,

Name: TeresaAdam

ID:676

Grade1: 78

Grade2:-1

Grade3: 98Average grade: 58.333333333333336

Letter grade:F, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]Thank you.

Corrections:

I want a space between the last and first name. It appears to be the the program just not printing out. I like to get rid of the comas after lettergrade. Last name on output has null, null....would like to fix.

Also in option B I would like to be able to enter the grade using the student ID.

I would like my array to implement without set number. I tried arraylist but my implementation was incorrect.

See Code below.

Main:

import java.util.Arrays;

import java.util.Scanner;

public class StudentClass {

public static void main(String[] args) {

{

Scanner input = new Scanner(System.in);

Student[] students = new Student[20];

int count = 0; // number of students

char option;

String sName;

String lName;

int sID;

int grade;

int index;

do {

System.out.println("---MENU---");

System.out.println("a. Add new student");

System.out.println("b. Enter test grades");

System.out.println("c. Display all students");

System.out.println("d. Exit the program");

System.out.print("Enter your option: ");

option = input.next().charAt(0);

switch (option) {

case 'a':

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

sName = input.next();

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

lName = input.next();

System.out.print(" Enter the id of the student: ");

sID = input.nextInt();

students[count] = new Student(sName, lName, sID);

count++;

break;

case 'b':

if (count == 0) {

System.out.println("No students are in the list.");

break;

}

System.out.print(" Enter number of student staring with one : ");

index = input.nextInt();

if (index < 0 || index < count) {

System.out.print("Enter grade 1 out of 3: ");

grade = input.nextInt();

students[index].setGrade(0, grade);

System.out.print("Enter grade 2 out of 3: ");

grade = input.nextInt();

students[index].setGrade(1, grade);

System.out.print("Enter grade 3 out of 3: ");

grade = input.nextInt();

students[index].setGrade(2, grade);

} else {

System.out.println("Invalid index! The index should be >=0 and < " + count);

}

break;

case 'c':

System.out.println(" Details of all students:");

if (count == 0) {

System.out.println("No students are in the list.");

break;

}

// Sort array by last name

Arrays.sort(students,0,count);

for (int i = 0; i < count; i++) {

System.out.print(Arrays.toString(students));

break;

}

case 'd':

System.out.println("Thank you.");

break;

default:

System.out.println("Invalid Option!");

}

System.out.println();

} while (option != 'd');

}

}

}// end of class

Class

public class Student implements Comparable {

private String firstName;

private String lastName;

private int id;

private int grades[] = new int[3];

// constructor for name and ID

public Student(String studentFirstName, String studentLastName, int rID) {

firstName = studentFirstName;

lastName = studentLastName;

id = rID;

grades[0] = -1;

grades[1] = -1;

grades[2] = -1;

}

// get private variable student name

public String getStudentName() {

return firstName + lastName;

}

// get private variable id

public int getrID() {

return id;

}

// get private index grades

public int getGrade(int index) {

return grades[index];

}

// get private variable grades

public int[] getGrades() {

return grades;

}

// method average

public double getAverage() {

return (grades[0] + grades[1] + grades[2]) / 3.0;

}

// method letter grade

public char getLetterGrade() {

double avgGrd = getAverage();

if (avgGrd >= 90)

return 'A';

else if (avgGrd >= 80)

return 'B';

else if (avgGrd >= 70)

return 'C';

else if (avgGrd >= 60)

return 'D';

else

return 'F';

}

public void setID(int rID) {

id = rID;

}

public void setGrade(int index, int grade) {

grades[index] = grade;

}

public void setGrades(int[] aGrades) {

grades[0] = aGrades[0];

grades[1] = aGrades[1];

grades[2] = aGrades[2];

}

// Return a string discription of the class

@Override

public String toString() {

return " Name: " + firstName + "" + lastName + " ID:" + id + " Grade1: " + grades[0] + " Grade2:" + grades[1]

+ " Grade3: " + grades[2] + " Average grade: " + getAverage() + " Letter grade:" + getLetterGrade();

}

@Override

public int compareTo(Student o) {

String name1 = this.lastName + " " + this.firstName;

String name2 = o.lastName + " " + o.firstName;

if(name1.compareTo(name2) < 0) {

return -1;

} else if(name1.compareTo(name2) > 0) {

return 1;

}

return 0;

}

}// end of class