C Program to Calculate Standard Deviation

C program to find standard deviation; Through this tutorial, we will learn how to find the standard deviation in c program.

Programs to Calculate Standard Deviation in C

• C Program to Find Standard Deviation
• C Program to Find Standard Deviation using Function

C Program to Find Standard Deviation

/* Standard Deviation - Calculate standard deviation of n numbers */

#include  <stdio.h>
#include  <math.h>

void  main()
{
    int  i, n, x[50] ;
    float  avg, std, sum = 0, s = 0 ;
    printf("Enter the number of elements: ") ;
    scanf("%d", &n) ;
    printf("Enter the elements:\n") ;
    for(i=0 ; i<n ; i++)
        {
            scanf("%d", &x[i]) ;
            sum=sum+x[i] ;
        }
    avg=sum/n ;
    for(i=0 ; i<n ; i++)
        s = s + pow(x[i]-avg, 2) ;
    std = sqrt(s/n) ;
    printf("The standard deviation of given numbers is %f",std);
    return 0;
}

The output of the above c program; as follows:

Enter the number of elements: 5
Enter the elements:
1
2
3
4
5
The standard deviation of given numbers is 1.414214

C Program to Find Standard Deviation using Function

// SD of a population
#include <math.h>
#include <stdio.h>
float calculateSD(float data[], int n);
int main() {
    int i, n;
    float data[50];
    printf("Enter the number of elements: ") ;
    scanf("%d", &n) ;
    printf("Enter the elements:\n") ;
    for (i = 0; i < n; ++i)
        scanf("%f", &data[i]);
    printf("\nStandard Deviation = %.6f", calculateSD(data, n));
    return 0;
}

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

The output of the above c program; as follows:

Enter the number of elements: 5
Enter the elements:
1
2
3
4
5
Standard Deviation = 1.414214

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