// Solution to Exercise 17
// (NDE, 2013-01-07)
#include <vector>
#include <iostream>
#include <numeric>
#include <cmath>
using namespace std;
int main()
{
// Populate vector with data
vector<double> data;
int num_values;
cout << "How many values do you want? ";
cin >> num_values;
for (int i = 0; i < num_values; ++i) {
double value;
cout << "Enter a value: ";
cin >> value;
data.push_back(value);
}
int size = data.size();
cout << "Vector has " << size << " elements" << endl;
// Compute mean
double sum = accumulate(data.begin(), data.end(), 0.0);
double mean = sum / size;
cout << "Mean = " << mean << endl;
// Compute and display standard deviation
sum = 0.0;
vector<double>::const_iterator i = data.begin();
for (; i != data.end(); ++i) {
double dev = *i - mean;
sum += dev*dev;
}
double std_dev = sqrt(sum / size);
cout << "Std dev = " << std_dev << endl;
return 0;
}