#include <iostream>
#include <iomanip>
#include <math.h>

double getAmount ();
double roundAmount (double exactAmount);
double calcAverage (double sum , int count);
double calcStdDev (double sum , double sumSquared , int count);
double calcDif (double exactSum , double roundedSum);

using namespace std;


//******************************************************



int main ()
{
double count = 0;
double exactAmount = 0;
double exactSum = 0;
double roundedAmount = 0;
double roundedSum = 0;
double exactSumSquared = 0;
double roundedSumSquared = 0;
double exactStdDev;
double roundedStdDev;
double exactAverage;
double roundedAverage;
double percentDif;

exactAmount = getAmount ();
roundedAmount = roundAmount (exactAmount);
exactSumSquared = exactSum * exactSum;
roundedSumSquared = roundedSum * roundedSum;

while (exactAmount > 0)
{
count++;
exactSum = exactSum + exactAmount;
roundedSum = roundedSum + roundedAmount;

exactAverage = calcAverage (exactSum , count);
roundedAverage = calcAverage (roundedSum , count);

exactStdDev = calcStdDev (exactSum , exactSumSquared , count);
roundedStdDev = calcStdDev (roundedSum , roundedSumSquared , count);

percentDif = calcDif (exactSum , roundedSum);

exactAmount = getAmount ();
}

cout << setiosflags(ios::fixed|ios::showpoint) << setprecision(2) << exactSum
	 << exactAverage << exactStdDev;


cout << endl;
cout << "Calculation       Exact       Rounded" << endl;
cout << "---------------------------------------" << endl;
cout << "Sum:		   " << exactSum << "	        " << roundedSum << endl;
cout << "---------------------------------------" << endl;
cout << "Average:            " << exactAverage << "          " << roundedAverage << endl;
cout << "---------------------------------------" << endl;
cout << "Std Dev:            " << exactStdDev << "            " << roundedStdDev << endl;

return 0;
}



//****************************************************


double getAmount ()
{
double userVal;
cout << "Enter a number (0 to quit): ";
cin >> userVal;

return userVal;
}

//*****

double roundAmount (double exactSum)
{
double roundedAmount;
roundedAmount = int((exactSum + 5) / 10) * 10;
return roundedAmount;
}

//*****

double calcAverage (double sum , int count)
{
double Average;
if (count > 0)
{
Average = sum / count;
return Average;
}
else
{
return -1;
}
}
//*****

double calcStdDev (double sum , double sumSquared , int count)
{
double StdDev;
if (count > 1)
{
StdDev = sqrt ((sumSquared) * (sum * sum)) / count;
return StdDev;
}
else
{
return -1;
}
}
//*****

double calcDif (double exactSum , double roundedSum)
{
double Difference;
Difference = ((fabs(exactSum - roundedSum)) / (exactSum)) * 100;
return Difference;
}

//*****