arraytest.java

Java 程序设计源码 只提供了部分

import java.util.Arrays;

class ArrayTest
{
        public static void main(String[] args)
        {
                int[] num1 = new int[]{1,2,3};
                int[] num2 = new int[3];
                
                System.arraycopy(num1,1,num2,1,num1.length - 1);
                
                for(int i = 0;i < num2.length;i++)
                {
                        System.out.println("num2[" + i + "]" + " = " + num2[i]);
                        
                }
                
                Point[] pts1 = new Point[]{new Point(1,1),new Point(2,2),new Point(3,3)};
                Point[] pts2 = new Point[3];
                
                System.arraycopy(pts1,0,pts2,0,pts1.length);
                
                for(int i = 0;i < pts2.length;i++)
                {
                        System.out.println("pts2[" + i + "]" + ": " + "x = " + pts2[i].x + "," + "y =" + pts2[i].y);
                        
                }
                
                int[] num = new int[]{3,1,2};
                
                Arrays.sort(num);
                
                for(int i = 0;i < num.length;i++)
                {
                        System.out.println("num[" + i + "]" + " = " + num[i]);
                        
                }
                
                int index = Arrays.binarySearch(num,3);//index 是排列后的下标
                
                System.out.println("index = " + index);
                System.out.println("element = " + num[index]);
                
                Student[] ss = new Student[]    {new Student(18,"zhangsan"),
                                                 new Student(20,"lisi"),
                                                 new Student(21,"wangwu"),
                                                 new Student(20,"mybole"),
                                                 new Student(21,"mybole")
                                                };
                                                                               
                Arrays.sort(ss);

                for(int i = 0;i < ss.length;i++)
                {
                        System.out.println(ss[i]);
                }
                
                int index1 = Arrays.binarySearch(ss,new Student(20,"lisi"));
                
                System.out.println("index1 = " + index1 );
                System.out.println(ss[index1]);
        }
}

class Student implements Comparable
{
        int num;
        String name;
        
        Student(int num,String name)
        {
                this.num = num;
                this.name = name;
        }
        
        public String toString()
        {
                return "number = " + num + " ," + "name = " + name;
        }
        
        public int compareTo(Object o)
        {
                Student s = (Student)o;
                //return num > s.num ? 1: (num == s.num ? 0: -1);
                
                
                //对age排序后，再用name排序，使用下面的语句，把上面的语句注释掉。
                int result = num > s.num ? 1: (num == s.num ? 0: -1);
                
                if(0 == result)
                {
                        result = name.compareTo(s.name);
                }
                
                return result;
        }
}

class Point
{
        int x,y;
        
        Point(int x,int y)
        {
                this.x = x;
                this.y = y; 
        }
}