instead of using $-1$ as sentinel$,$ use Yes or No to continue with grades : import java.util.Scanner;

public class Loops $\{$

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

$//$ TODO Auto$-$generated method stub

$//$participation problem for week $3$

$//$instead of using $-1$ as sentinel

$//$use yes or no to continue with grades

int numStudents $=0$;

System.out.println$("$Please enter the grade of the first student: $")$;

Scanner inp $=$ new Scanner$($ System.in$)$;

double grade $=$ inp.nextDouble$()$;

double sumGrades $=0\mathrm{.}0$;

while$($ grade $!=-1)\{$

sumGrades $+=$ grade;

numStudents$++$;

System.out.println$("$Keep entering grades when you are done enter $-1")$;

System.out.println$("$Please enter the grade of the next student: $")$;

inp $=$ new Scanner$($ System.in$)$;

grade $=$ inp.nextDouble$()$;

$\}$

if$($ numStudents $!=0)$

$\{$

double average $=$ sumGrades$/$numStudents;

System.out.println$($ "Average grade of $"+$ numStudents $+"$ students is $"+$ average$)$;

$\}$

else

System.out.println$("$Number of students is zero and cannot calculate an average."$)$;

$\}$

$\}$