Assume that the data is provided in a file called Ch$5\_$Ex$18$Data.txt and the first line in the file specifies the cost of one box.

Modify the program $($in main.cpp$)$ so that it uses an EOF$-$controlled loop to process the data from the text file.

#include

#include

#include

using namespace std;

const string SENTINEL $="-1"$;

int main$()$

$\{$

string name;

int numOfVolunteers;

int numOfBoxesSold;

int totalNumOfBoxesSold;

double costOfOneBox;

cout $<<$ fixed $<<$ showpoint $<<$ setprecision$(2)$;

cout $<<$ "Line $14$: Enter each volunteer's name and $"$

$<<$ "the number of boxes $"<<$ endl

$<<"$ sold by each volunteer, ending $"$

$<<$ "with $-1$: $"<<$ endl;

totalNumOfBoxesSold $=0$;

numOfVolunteers $=0$;

cin $>>$ name;

while $($name $!=$ SENTINEL$)$

$\{$

cin $>>$ numOfBoxesSold;

totalNumOfBoxesSold $=$ totalNumOfBoxesSold

$+$ numOfBoxesSold;

numOfVolunteers$++$;

cin $>>$ name;

$\}$

cout $<<$ endl;

cout $<<$ "Line $26$: The total number of boxes sold: $"$

$<<$ totalNumOfBoxesSold $<<$ endl;

cout $<<$ "Line $27$: Enter the cost of one box: $"$;

cin $>>$ costOfOneBox;

cout $<<$ endl;

cout $<<$ "Line $30$: The total money made by selling $"$

$<<$ "cookies: $$"$

$<<$ totalNumOfBoxesSold $*$ costOfOneBox $<<$ endl;

if $($numOfVolunteers $!=0)$

cout $<<$ "Line $32$: The average number of $"$

$<<$ "boxes sold by each volunteer: $"$

$<<$ totalNumOfBoxesSold $/$ numOfVolunteers

$<<$ endl;

else

cout $<<$ "Line $34$: No input." $<<$ endl;

return $0$;

$\}$