### C Code Snippets 6 - Average and Standard Deviation Calculation Using an Array

The following program takes N number of elements from user(where, N is specified by user), stores data in an array and calculates the average and the standard deviation of those numbers.

``````
/**
* Author : Berk Soysal
*/

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

int main()
{
//Define the integer Variables
int i, N;

printf("\nThis Program Calculates the Average");
printf(" and the Standard Dev. of the Entered Values;\n\n");
printf("How Many Numbers ? :");
scanf("%d",&N); //Get the number of elements of the array
printf("\n");
double average, sum=0.0,std, x[N];

//Calculate the SUM
for(i=0; i<N; i++)
{
printf("%d. number : ",i+1);
scanf("%lf",&x[i]);

sum += x[i];
}
//Calculate the Average
average = sum/N;

// Calculate the Standard Deviation
for(sum = 0.0, i=0; i<N; i++)
{
sum += (x[i]-average)*(x[i]-average);
}

std = sqrt( sum/(N-1) );

//Print
printf("\nThe Average is = %1.3lf\n",average);
printf("\nThe Standard Deviation is = %1.3lf\n",std);
return 0;
}

``````

Result