C program to calculate standard deviation

In this tutorial, we are going to write a C Program to calculate standard deviation in C Programming with practical program code and step-by-step full complete explanation.

C Program to calculate the standard deviation.

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

#define MAXSIZE 100

void main()
{
    int i,n;
    float value[MAXSIZE], deviation;
    
    int sum,sumsqr,n=0;
    
    float mean, variance, stddeviation;

    printf("Input values: input -1 to end\n");

    for(i=1;i<MAXSIZE;i++)
    {
        scanf("%f",&value[i]);

        if(value[i]== -1)
            break;
        sum += value[i];
        n+=1;
    }

    mean=sum/(float)n;

    for(i=1;i<=n;i++)
    {
        deviation = value[i]-mean;
        sumsqr += deviation*deviation;
    }

    variance = sumsqr/(float)n;
    stddeviation=sqrt(variance);

    printf("\nNumber of items: %d",n);
    printf("\nMean: %f",mean);
    printf("\nStandard deviation: %f",stddeviation);
}

Output

 
Input values: input -1 to end
65 9 27 78 12 20 33 49 -1

Number of items: 8
Mean: 36.625000
Standard deviation: 23.510303