public class TestScoresModel{
private Student[] students; // Array of students
private int indexSelectedStudent; // Position of current student
private int studentCount; // Current number of students
public TestScoresModel(){
// Initialize the data
indexSelectedStudent = -1;
studentCount = 0;
students = new Student[10];
}
// Mutator methods for adding and replacing students
public String add(Student s){
if (studentCount == students.length)
return "SORRY: student list is full";
else{
students[studentCount] = s;
indexSelectedStudent = studentCount;
studentCount++;
return null;
}
}
public String replace(Student s){
if (indexSelectedStudent == -1)
return "Must add a student first";
else{
students[indexSelectedStudent] = s;
return null;
}
}
// Navigation methods
public Student first(){
Student s = null;
if (studentCount == 0)
indexSelectedStudent = -1;
else{
indexSelectedStudent = 0;
s = students[indexSelectedStudent];
}
return s;
}
public Student previous(){
Student s = null;
if (studentCount == 0)
indexSelectedStudent = -1;
else{
indexSelectedStudent
= Math.max (0, indexSelectedStudent - 1);
s = students[indexSelectedStudent];
}
return s;
}
public Student next(){
Student s = null;
if (studentCount == 0)
indexSelectedStudent = -1;
else{
indexSelectedStudent
= Math.min (studentCount - 1, indexSelectedStudent + 1);
s = students[indexSelectedStudent];
}
return s;
}
public Student last(){
Student s = null;
if (studentCount == 0)
indexSelectedStudent = -1;
else{
indexSelectedStudent = studentCount - 1;
s = students[indexSelectedStudent];
}
return s;
}
// Accessors to observe data
public Student currentStudent(){
if (indexSelectedStudent == -1)
return null;
else
return students[indexSelectedStudent];
}
public int size(){
return studentCount;
}
public int currentPosition(){
return indexSelectedStudent;
}
public int getClassAverage(){
if (studentCount == 0)
return 0;
int sum = 0;
for (int i = 0; i < studentCount; i++)
sum += students.getAverage();
return sum / studentCount;
}
public Student getHighScore(){
if (studentCount == 0)
return null;
else{
Student s = students[0];
for (int i = 1; i < studentCount; i++)
if (s.getHighScore() < students.getHighScore())
s = students;
return s;
}
}
public String toString(){
String result = "";
for (int i = 0; i < studentCount; i++)
result = result + students + "\n";
return result;
}
}
import java.util.Scanner;
public class TestScoresView{
private TestScoresModel model;
public TestScoresView(TestScoresModel m){
model = m;
run();
}
// Menu-driven command loop
private void run(){
while (true){
System.out.println("start of run method");
System.out.println("Number of students: " + model.size());
System.out.println("Index of current student: " +
model.currentPosition());
displayMenu();
int command = getCommand("Enter a number [1-11]: ", 1, 11);
if (command == 11)
break;
runCommand(command);
}
}
private void displayMenu(){
System.out.println("MAIN MENU");
System.out.println(" 1. Display the current student");
System.out.println(" 2. Display the class average");
System.out.println(" 3. Display the student with the highest grade");
// missing code
System.out.println("11. Quit the program");
}
// Prompts the user for a command number and runs until
// the user enters a valid command number
// Parameters: prompt is the string to display
// low is the smallest command number
// high is the largest command number
// Returns: a valid command number
private int getCommand(String prompt, int low, int high){
// errors checking
Scanner reader = new Scanner(System.in);
int command = low - 1;
while (command < low || command > high){
System.out.print(prompt);
command = reader.nextInt();
if (command < low || command > high)
System.out.println("Error: command must be between " +
low + " and " + high);
}
return command;
}
// Selects a command to run based on a command number,
// runs the command, and asks the user to continue by
// pressing the Enter key
private void runCommand(int command){
if (command == 1)
displayStudent();
else if (command == 2)
System.out.println("Average score = " + model.getClassAverage());
//missing code
}
private void displayStudent(){
Student s = model.currentStudent();
if (s == null)
System.out.println("No student is currently available");
else
System.out.println(s);
}
private void displayHighScore(){
Student s = model.getHighScore();
if (s == null)
//missing code
else
//missing code
}
private void addStudent(){
Student s = new Student();
Scanner reader = new Scanner(System.in);
System.out.print("Enter the name: ");
s.setName(reader.nextLine());
for (int i = 1; i <= s.getNumberOfTests(); i++){
//missing code
}
String message = s.validateData();
if (message != null)
System.out.println(message);
else{
message = model.add(s);
if (message != null)
System.out.println(message);
else
System.out.println("Student added");
}
}
private void editStudent(){
Student s = model.currentStudent();
if (s == null)
System.out.println("No student is currently available");
else{
// Work on a temporary copy
Student temp = new Student(s);
String menu = "EDIT MENU\n" +
"1. Change the name\n" +
"2. Change a score\n" +
"3. View the student\n" +
"4. Quit this menu\n";
Scanner reader = new Scanner(System.in);
int command = 1;
while (command != 4){
System.out.print(menu);
command = getCommand("Enter a number [1-4]: ", 1, 4);
if (command == 1){
//lots of missing code
}else{
// Check for valid data before writing to database
String message = temp.validateData();
if (message != null)
System.out.println(message);
else
model.replace(temp);
}
}
}
}
}
Do you think it is good? Bad? And why?
After reading through it I decided to improve on it because some parts of it looked like they could be better designed. This is my completed code for the view file, you can also see that I basically rewrote the whole thing.
/*
* Test Scores View
*/
import java.util.Scanner;
public class TestScoresView
{
private TestScoresModel model;
private Scanner scanner;
public TestScoresView(TestScoresModel newModel)
{
model = newModel;
scanner = new Scanner(System.in);
run();
}
private void run()
{
int command = 0;
while (command != 11)
{
System.out.println("Number of students: " + model.size());
System.out.println("Current student index: " + model.currentPosition());
System.out.println();
displayMenu();
command = getCommand("Enter a number [1-11]: ", 1, 11);
runCommand(command);
}
}
private void displayMenu()
{
String[] menuOptions =
{
"Display current student",
"Display class average",
"Display student with highest grade",
"Display all students",
"Edit current student",
"Add new student",
"Go to first student",
"Go to last student",
"Go to next student",
"Go to previous student",
"Quit the program"
};
for (int c = 0; c < menuOptions.length; c++)
System.out.println((c + 1) + ": " + menuOptions[c]);
System.out.println();
}
private int getCommand(String prompt, int min, int max)
{
// Keep prompting for input until valid input is received
int command = min - 1;
while (command < min || command > max)
{
try
{
System.out.print(prompt);
command = Integer.parseInt(scanner.nextLine());
}
catch (Exception exception)
{
command = min - 1;
continue;
}
}
return command;
}
private void runCommand(int command)
{
switch (command)
{
case 1:
System.out.println((model.size() > 0) ? model.currentStudent() : "There are no students.");
break;
case 2:
System.out.println("The class average is " + model.getClassAverage());
break;
case 3:
Student highScoreStudent = model.getHighScore();
System.out.println((highScoreStudent != null) ?
"The student " + highScoreStudent.getName() + " got the highest score of " + highScoreStudent.getHighScore()
: "There are no students yet.");
break;
case 4:
System.out.println((model.size() > 0) ? model : "There are no students.");
break;
case 5:
editStudent();
break;
case 6:
addStudent();
break;
case 7:
System.out.println((model.size() > 0) ? model.first() : "There are no students.");
break;
case 8:
System.out.println((model.size() > 0) ? model.last() : "There are no students.");
break;
case 9:
System.out.println((model.size() > 0) ? model.next() : "There are no students.");
break;
case 10:
System.out.println((model.size() > 0) ? model.previous() : "There are no students.");
break;
}
// Wait for enter key to be pressed before continuing
if (command >= 1 && command <= 10)
{
System.out.println("Press the enter key to continue.");
scanner.nextLine();
}
}
private void addStudent()
{
Student newStudent = getStudentInput();
String errors = newStudent.validateData();
if (errors == null)
{
if (model.add(newStudent))
{
System.out.println("Student has successfully been added.");
}
else
{
System.out.println("The list of students is full, so the student was not added.");
}
}
else
{
System.out.println(errors);
}
}
private void editStudent()
{
if (model.size() > 0)
{
Student updatedStudent = getStudentInput();
String errors = updatedStudent.validateData();
if (errors == null)
{
System.out.println("Student has successfully been edited.");
model.replace(updatedStudent);
}
else
{
System.out.println(errors);
}
}
else
{
System.out.println("There are no students to edit.");
}
}
private Student getStudentInput()
{
String name = "";
int[] tests;
int testCount = 0;
while (name.length() == 0)
{
System.out.println("Enter the student's name: ");
name = scanner.nextLine();
}
while (testCount <= 0)
{
System.out.println("How many tests does this student have: ");
try
{
testCount = Integer.parseInt(scanner.nextLine());
}
catch (Exception exception)
{
testCount = 0;
continue;
}
}
tests = new int[testCount];
for (int c = 0; c < testCount; c++)
{
int score = -1;
while (score < 0 || score > 100)
{
System.out.println("Enter score for test #" + (c + 1) + ": ");
try
{
score = Integer.parseInt(scanner.nextLine());
}
catch (Exception exception)
{
score = -1;
continue;
}
}
tests[c] = score;
}
return new Student(name, tests);
}
}
What do you think of this code and how do you think I can improve it?
