Question

Sentinel While Loop Lab

Convert Lab 11 from a counter controlled WHILE loop to a sentinel WHILE loop. Do the following:

• Prompts the user to enter a grade or a -1 to quit.
• IF the user entered a -1 THEN
  • Display a message that the User is done entering grades
• ELSE
  • Count each grade as it is entered.
  • Compute a running total of the grades entered.
• END IF
• After the user enters the sentinel of -1, calculate the average of the grades entered.
• When computing the average, make sure that there is no division by zero. Check to make sure the counter is not equal to zero.
• Make sure the sentinel is not counted as a grade.
• Print out a message stating the average of the grades entered.

Include the following:

1. Use a sentinel-controlled WHILE loop that uses a -1 as the sentinel to exit the loop.
   • Before counting the grades, initialize the counter to zero before the while loop begins.
2. While within the body of the ELSE:
   • Within the WHILE loop:
     • Prompt the User to enter a grade or a -1 to quit.
     • IF the input is not a -1 THEN
       • Count the grade.
       • Compute a running total of these grades as they are entered.
     • END IF
   • After the WHILE Loop is done executing, compute the average of all the grades entered. Remember to check to make sure you don't perform a division by zero.

NOTE 1:

• DO NOT use the "return 0" code, end, break, or exit to force an exit from within your IF/ELSE structure.  Declare all variables within the data declaration section.
  • Let the program progress to the end of the main function.
  • The end of the main function is the only place that the “return 0” should be placed.
  • A SWITCH statement is the only place that the break command should be used.
• DO NOT use the "continue" statement.

NOTE 2:

1. Declare all variables within the data declaration section of each class and method.  (-.1)
2   Do not get input on the same line as a variable declaration.  (-.1)
3. Do not place an equation for computation on the same line as declaring a variable.  (-.1)
4. Do not place an equation for computation on the same line as an output statement.  (-.1)

Answer 1

Answer: Hey!! dear student kindly find your solution below.Let me know if any issue. Thanks.

Copy to code: This code asks for grades from user and continue asks until sentinel value is entered.After entering sentinel value,user display a message and average of the grades.

You didn't mention any language so C++ used here if any change you want just comment me in the comment box.

#include<iostream>
using namespace std;
int main()
{
   int counter = 0;//declaration of varaibles
   double grade,sum = 0,avg;
  
   while(grade!=-1)//whle loop until sentinel value is entered
   {
       cout<<"Enter grades: ";//prompts for grades
       cin>>grade;
      
       if(grade>0)//if grade not less than 0
       {
           counter++; //increment of counter
           sum = sum+grade;//sum of grades
       }
       else
       if(grade==-1)//if sentinel vlaue is entered
       {
           cout<<"User is done entering grades";//display message
       }
   }
   if(counter!=0)//check counter if not equal to 0
   {
       avg = sum/counter;
   }
   cout<<"\nAverage of grades: "<<avg;
   return 0;  
}

Snapshot of code and output:

Java Code:

import java.util.*;
import java.util.Scanner;
class Main
{
public static void main(String[]args)
{
int counter = 0;//declaration of varaibles
double grade = 0,sum = 0,avg= 0.0;
Scanner sc = new Scanner(System.in);
  
while(grade!=-1)//while loop until sentinel value is entered
{
System.out.println("Enter grades: ");//prompts for grades
grade = sc.nextDouble();
  
if(grade>0)//if grade not less than 0
{
counter++; //increment of counter
sum = sum+grade;//sum of grades
}
else
if(grade==-1)//if sentinel vlaue is entered
{
System.out.println("User is done entering grades");//display message
}
}
if(counter!=0)//check counter if not equal to 0
{
avg = sum/counter;
}
System.out.println("Average of grades: "+avg);
}
}