the folloeing program manipulates the median of an array but is retutning a NullPointerException.i have tried but didnt fix it.plz any1 to sortout the bug.
thanks in advance
import java.io.*;
public class media {
@SuppressWarnings("null")
public static void main(String[] args) {
int i=0,j=0,n=0;
float median;
float t;
int []a=null;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the number of items\n");
try {
n=Integer.parseInt(br.readLine());
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Input values \n");
for( i=1;i<n;i++)
try {
a[i]=Integer.parseInt(br.readLine());
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/* Reading items in array a */
/* Sorting begins */
for (i = 1 ; i <= n-1 ; i++)
{ /* Trip-i begins */
for (j = 1 ; j <= n-i ; j++)
{
if (a[j] <= a[j+1])
{ /* Interchanging values */
t = a[j];
a[j] = a[j+1];
a[j+1] = (int) t;
}
else continue ;
}
} /* sorting ends */
/* calculation of median */
if ( n % 2 == 0)
median = (float) ((a[n/2] + a[n/2+1])/2.0) ;
else
median = a[n/2 + 1];
/* Printing */
for (i = 1 ; i <= n ; i++)
{
System.out.println(a[i]);
}
System.out.println("\n\nMedian is " +median);
}
}