C++ Help! I have this following code and it works to find the average. But now I

Question

C++ Help!

I have this following code and it works to find the average. But now I need to find the standard deviation and im not sure where to start. I have it prompt a user to how many values they will enter in, it will then ask for the values and put the values in a vector. Afterwards it calculates the average. Now I just need it to calculate the standard deviation. Nothing fancy, I need it to be relatively simple really. Here is the code I have so far.

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main()
{
// Create vector
vector<double> values;

// Declare variables
double count;
double value;
double average = 0;
double stdDev;
double var;
  
// Prompt user and get the number of values
cout << "How many values will you enter? ";
cin >> count;

// Get the values from user and calculate average
for( double i = 0; i<= count; i++)
{
cin >> value;
values.push_back(value);
average+=values[i];
  
  
}
cout << average/count << ' ';

  
return 0;
}

Explanation / Answer

#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main()
{
    /* Create vector */
    vector<double> values;

    /* Declare variables*/
    double count;
    double value;
    double average = 0;
    double stdDev;
    double var=0;
  
    /* Prompt user and get the number of values */
    cout << "How many values will you enter? ";
    cin >> count;

    /* Get the values from user and calculate average */
    for( double i = 0; i < count; i++)
    {
        cin >> value;
        values.push_back(value);
        average+=values[i];
    }
    average = average/count ;
    cout << "average = "<<average << ' ';
  
    //Variance Calculation
    for( double i = 0; i < count; i++)
        var += ( average - values[i] ) * ( average - values[i] );
    var /= count;
    cout << "variance = "<<var << ' ';
    //STandard Deviation Calculation
    stdDev = sqrt(var);
    cout << "standard deviation = "<<stdDev << ' ';

    return 0;
}

----------------------------

Input :

5
2
3
4
5
6

Ouput:

--------------------

average = 4
variance = 2
standard deviation = 1.41421

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