In this post, we will learn **how to calculate standard deviation using C** Programming language.

A **Standard Deviation** is a statistic that measures how much the members of a group differ from the mean value of the group.

To calculate the standard deviation, we have to follow these steps:

- Find out the Mean
- Then for each element, subtract the Mean and Square the result
- Then work out the Mean of those squared differences
- Take the square root of that

We will be using the exact same procedure in our program to compute the standard deviation.

So, without further ado, let’s begin this tutorial.

**C Program To Calculate Standard Deviation**

// C Program To Calculate Standard Deviation #include <stdio.h> #include <math.h> int main(){ int i, n; float num[25]; float sum = 0.0, mean, SD; // Asking for input printf("Enter total number of elements: "); scanf("%d", &n); printf("Enter the value of elements: \n"); for (i = 0; i < n; i++ ) scanf("%f", &num[i]); // Calculating Mean for (i = 0; i < n; i++) sum += num[i]; mean = sum / n; // Calculating Standard Deviation sum = 0.0; for (i = 0; i < n; i++) sum += (num[i] - mean) * (num[i] - mean); SD = sqrt(sum / n); printf("Mean: %6.3f \n", mean); printf("Standard Deviation: %.6f", SD); return 0; }

**Output**

```
Enter total number of elements: 10
Enter the value of elements:
1
2
3
4
5
6
7
8
9
10
Mean: 5.500
Standard Deviation: 2.872281
```

**How Does This Program Work ?**

int i, n; float num[25]; float sum = 0.0, mean, SD;

In this program, we have declared two int data type variables named **i** and **n**. We have also declared four float data type variables named as **sum**, **mean**, **num** and **SD**.

// Asking for input printf("Enter total number of elements: "); scanf("%d", &n); printf("Enter the value of elements: \n"); for (i = 0; i < n; i++ ) scanf("%f", &num[i]);

Then, the user is asked to enter the total number of elements and value of each of the elements.

// Calculating Mean for (i = 0; i < n; i++) sum += num[i]; mean = sum / n;

We calculate the Mean by adding all the elements and dividing that number by the total number of elements.

// Calculating Standard Deviation sum = 0.0; for (i = 0; i < n; i++) sum += (num[i] - mean) * (num[i] - mean); SD = sqrt(sum / n);

Now, we subtract each element by the mean and square the result. Then, we take out the square root of that number(Mean of Squared Differences). Hence, we obtain the standard Deviation.

printf("Mean: %6.3f \n", mean); printf("Standard Deviation: %.6f", SD);

Finally, the value of Mean and Standard Deviation is printed on the screen using **printf()** function.

**Conclusion**

I hope after going through this post, you understand **how to calculate standard deviation using C **Programming language.

If you have any doubt regarding the program, feel free to contact us in the comment section. We will be delighted to help you.

**Also Read:**

cyrusIn calculation of standard deviation in line fourth SD = sqrt(sum / n); is wrong instead it should be SD = sqrt(sum / n-1); for correct calculation of SD. THANKS IT HELP ME TO FIGURE ME OUT MY ERROR.