import java.util.ArrayList;

$/**$

$*$ A class to track a student's name and a list of numeric grades for

$*$ that student.

$*$

$*$ @author Jim Teresco

$*$ @version Fall $2019$

$*/$

public class StudentGrades $\{$

$//$ we have a student's name and a list of that student's grades

$//$ as the fields for this class

private String name;

private ArrayList grades;

$/**$

$*$ Construct a new student, who has no grades when starting out.

$*$

$*$ @param name The student's name.

$*/$

public StudentGrades$($String name$)\{$

this.name $=$ name;

grades $=$ new ArrayList$()$;

$\}$

$/**$

$*$ Add a grade to a for the student.

$*$

$*$ @param The grade to add to this student's grade list.

$*/$

public void addGrade$($double grade$)\{$

grades.add$($grade$)$;

$\}$

$/**$

$*$ Get this student's name.

$*$

$*$ @return The student's name.

$*/$

public String getName$()\{$

return name;

$\}$

$/**$

$*$ Determine equality of StudentGrades objects, defined such that two StudentGrades objects

$*$ are equal if they have the same name field

$*$

$*$ @param obj The other object.

$*$ @return true If this and obj have the same name field.

$*/$

public boolean equals$($Object obj$)\{$

StudentGrades other $=($StudentGrades$)$ obj;

return other.name.equals$($name$)$;

$\}$

$/**$

$*$ Returns a string representing the StudentGrade object.

$*$

$*$ @return Returns a string representing the StudentGrade object.

$*/$

@Override

public String toString$()\{$

StringBuilder s $=$ new StringBuilder$($name $+"$:$")$;

for $($double score : grades$)\{$

s$.$append$(""+$ score$)$;

$\}$

return s$.$toString$()$;

$\}$

$\}$

import java.util.ArrayList;

import java.util.Scanner;

$/**$

$*$ Example CourseGrades: a program to keep track of course

$*$ grades for a group of students. Uses ArrayLists in a few

$*$ ways.

$*$

$*$ @author Jim Teresco

$*$ @version Fall $2019$

$*/$

public class CourseGrades $\{$

$//$ We will have some instance variables to track the

$//$ contents of the list of students and their grades

$//$ and a set of methods to interact with the list, which

$//$ is done from main, below.

private ArrayList studentList;

$/**$

$*$ Construct an empty CourseGrades.

$*/$

public CourseGrades$()\{$

studentList $=$ new ArrayList$()$;

$\}$

$/**$

$*$ Method to add a grade for a $($possibly new$)$ student.

$*$

$*$ @param name The student's name.

$*$ @param grade The grade to add for this student.

$*/$

public void add$($String name, double grade$)\{$

StudentGrades sg $=$ findStudentGradesByName$($name$)$;

if $($sg $!=$ null$)\{$

sg$.$addGrade$($grade$)$;

$\}$

else $\{$

sg $=$ new StudentGrades$($name$)$;

sg$.$addGrade$($grade$)$;

studentList.add$($sg$)$;

$\}$

$\}$

$/**$

$*$ Print out all of the students and their grades.

$*/$

public void printAll$()\{$

for $($StudentGrades sg : studentList$)\{$

System.out.println$($sg$)$;

$\}$

$\}$

$/*$

$*$ Private helper method to look up the StudentGrades object

$*$ from the list that matches the name. Returns null if none.

$*/$

private StudentGrades findStudentGradesByName$($String name$)\{$

for $($StudentGrades sg : studentList$)\{$

if $($sg$.$getName$().$equals$($name$))$ return sg;

$\}$

return null;

$\}$

$/**$

$*$ This is the main method for your program.

$*$

$*$ @param args No command line arguments are required.

$*/$

public static void main$($String$[]$ args$)\{$

CourseGrades cg $=$ new CourseGrades$()$;

cg$.$add$("$Linus$",83\mathrm{.}5)$;

cg$.$add$("$Snoopy$",95)$;

cg$.$add$("$Linus$",91)$;

$\}$

$\}$

make memory diagram for main method of the CourseGrades class is executed and the program is currently executing

the last line in the main method:

cg$.$add$($Linus$,91)$;

right before the call it makes to

sg$.$addGrade$($grade$)$;

returns.