# C Program to Calculate Standard Deviation

To understand this example, you should have the knowledge of the following C programming topics:

This program calculates the standard deviation of an individual series using arrays. Visit this page to learn about Standard Deviation.

To calculate the standard deviation, we have created a function named `calculateSD()`.

## Example: Population Standard Deviation

``````// SD of a population
#include <math.h>
#include <stdio.h>
float calculateSD(float data[]);
int main() {
int i;
float data[10];
printf("Enter 10 elements: ");
for (i = 0; i < 10; ++i)
scanf("%f", &data[i]);
printf("\nStandard Deviation = %.6f", calculateSD(data));
return 0;
}

float calculateSD(float data[]) {
float sum = 0.0, mean, SD = 0.0;
int i;
for (i = 0; i < 10; ++i) {
sum += data[i];
}
mean = sum / 10;
for (i = 0; i < 10; ++i) {
SD += pow(data[i] - mean, 2);
}
return sqrt(SD / 10);
}
``````

Output

```Enter 10 elements: 1
2
3
4
5
6
7
8
9
10

Standard Deviation = 2.872281
```

Here, the array containing 10 elements is passed to the `calculateSD()` function. The function calculates the standard deviation using mean and returns it.

Note: The program calculates the standard deviation of a population. If you need to find the standard deviation of a sample, the formula is slightly different.