//ForStatistics.cc
//Computes the sample mean and variance of N numbers input at the keyboard.
//N is specified by the user but must be 10 or fewer in this example.

#include <iostream>
using namespace std;

int main()
{
   int    N=0;
   float  number, sum=0.0, sumSquares=0.0;
   float  mean, variance;

   // Wait until the user inputs a number in correct range (1-10)
   // Stay in loop if input is outside range
   while(N<1 || N>10)
   {
      cout << "Number of entries (1-10) = ";
      cin  >>   N;
   }

   // Execute loop N times
   // Start with i=1 and increment on completion of loop. 
   // Exit loop when i = N+1;
   for(int i=1; i<=N; i++ )
   {
       cout << "Input item number " << i << " = ";
       cin >> number;
       sum = sum + number;
       sumSquares = sumSquares + number*number;
   }

   mean = sum/N;
   variance = sumSquares/N - mean*mean;
   
   cout << "The mean of the data is " << mean << 
          " and the variance is " << variance << endl;

   return 0;
}