提示为Exception in thread "main" java.lang.NullPointerException
at chapter5.Java_2.main(Java_2.java:41)
代码:
class newPoint{
int x;
int y;
}
public class Java_2 {
public static float newsqrt(newPoint a) {
return (float) Math.sqrt((a.x*a.x+a.y*a.y));
}
public static void sort(newPoint a[],float dis[]) {
for(int i=0;i
dis[i]=newsqrt(a[i]);
}
for(int i=0;i
for(int j=i+1;j
if(dis[i]>dis[j]) {
newPoint temp=a[i];
a[i]=a[j];
a[j]=temp;
float b=dis[i];
dis[i]=dis[j];
dis[j]=b;
}
}
}
}
public static void newprint(newPoint a[],float dis[]) {
System.out.print("距原点距离由小到大的点顺序为:");
for(int i=0;i<a.length;i++) {
System.out.print("("+a[i].x+","+a[i].y+")"+" ");
}
System.out.print("\n"+"距离由小到大分别为:");
for(int i=0;i<dis.length;i++) {
System.out.print(dis[i]+" ");
}
}
public static void main(String[] args) {
newPoint arr[]=new newPoint[10];
float dis[]=new float[arr.length];
for(int i=0;i<arr.length;i++) {
arr[i].x=(int)(Math.random()*50);
arr[i].y=(int)(Math.random()*50);
}
sort(arr,dis);
newprint(arr,dis);
}
}