#include <iostream> //access cout
#include <cmath>   // access power functions
#include <iomanip> // access fixed and setprecision

using namespace std;

int main()
{    
    int number1, number2, number3, number4;
    float mean;
    float standardDeviation;
    const float N = 4.0;
    
    
    //put output for formatting
    cout << fixed << setprecision(2);

    //input the four numbers
    cout << "Input the 1st number: ";
    cin >> number1;
    
    cout << "Input the 2nd number: ";
    cin >> number2;
    
    cout << "Input the 3rd number: ";
    cin >> number3;
    
    cout << "Input the 4th number: ";
    cin >> number4;

    //calculate the mean and output the mean
     mean = ((number1 + number2 + number3 + number4)/N);
     cout << "The mean of these numbers is: " <<  mean << endl;
    
     cout << endl;

    //calculate standard deviation and output standard deviation
    standardDeviation = sqrt((pow(number1-mean,2) + pow(number2-mean,2) +
                              pow(number3-mean,2) + pow(number4-mean,2)/ (N-1);
    cout << "The standard deviation is: " << standardDeviation << endl;
    
    cout << endl;
  
    cin.get(); //type enter to end
    cin.get(); //type enter to end

}

system("PAUSE");
return 0;

#include <iostream>
#include <limits>

int main()
{
  
  // Rest of the code    
  
  //Clean the stream and ask for input
  std::cin.ignore (std::numeric_limits<std::streamsize>::max(), '\n' );
  std::cin.get();
}