# C++ : Calculate Standard Deviation

Tutorial by:Manisha Dubey      Date: 2016-06-18 04:52:38

In this program, elements of arrays are used for storing the data and this array is passed to function which calculates standard deviation and finally the result(standard deviation) is displayed in `main()` function.

## Source Code to Calculate Standard Deviation by Passing it to Function

``````
/* Source code to calculate standard deviation. */

#include <iostream>
#include <cmath>
using namespace std;
float standard_deviation(float data[], int n);
int main()
{
int n, i;
float data[100];
cout << "Enter number of data: ";
cin >> n;
while (n>100 || n<=0)
{
cout << "Error! number should in range of (1 to 100)." << endl;
cout << "Enter the number of data again: ";
cin >> n;
}
cout << "Enter elements: " << endl;
for(i=0; i<n; ++i)
cin >> data[i];
cout << endl;
cout << "Standard Deviation = " << standard_deviation(data,n);
return 0;
}
float standard_deviation(float data[], int n)
{
float mean=0.0, sum_deviation=0.0;
int i;
for(i=0; i<n;++i)
{
mean+=data[i];
}
mean=mean/n;
for(i=0; i<n;++i)
sum_deviation+=(data[i]-mean)*(data[i]-mean);
return sqrt(sum_deviation/n);
}``````

Output

```
Enter number of datas: 4
Enter elements:
1
2
3
4

Standard Deviation = 1.11803
```

## C++

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