5.Standard deviation

import java.util.*;
import java.lang.*;
class sd
{
    public static void main(String args[])
    {
        int mean,var,sum=0;
        double std;
        Scanner t = new Scanner (System.in);
        System.out.println("enter total no. of numbers");
        int n = t.nextInt();
        int i;
        int a[] = new int[n];
        System.out.println("enter numbers");
        for(i=0;i<n;i++)
        {
        a[i] = t.nextInt();
        }
        for(i=0;i<n;i++)
        {
            sum=sum+a[i];
        }
        mean = sum/n;
        sum=0;
        for(i=0;i<n;i++)
        {
            sum = sum+((a[i]-mean)*(a[i]-mean));
        }
        var = sum/n;
        std = Math.sqrt(var);
        System.out.println("Standard deviation is "+std);
    }
}