求助:Exception in thread "main" java.lang.NullPointerException at myjava.main(myjava:12)

[Langtao851]

import java.awt.*;
import java.io.*;
import java.util.*;
public class myjava
{
public static void main(String args[])
{
Point a[]=new Point[10];
double min=0.0;
for(int i=0;i<10;i++)
{
a[i].inputx(Math.random()*10);
a[i].inputy(Math.random()*10);
min=a[i].getlength();
int k=i;
for(int j=i+1;j<10;j++)
{
if(a[j].getlength()<min)
{
min=a[j].getlength();k=j;
}
}
Point temp=a[k];
a[k]=a[i];
a[i]=temp;
System.out.println("点("+a[i].getx()+","+a[i].gety()+")与原点距离为："+a[i].getlength());
}
}
}
class Point
{
private double x;
private double y;
public double getlength()
{
double e=Math.sqrt(x*x+y*y);
return e;
}
public double getx()
{
return x;
}
public double gety()
{
return y;
}
public void inputx(double x1)
{
x=x1;
}
public void inputy(double y1)
{
y=y1;
}
}