在Java中随机生成的数组中找到第二高的数字

Question

Hey guys I have a homework problem that asks me to find the second highest number of a randomly generated array and to return that number. the array has to be of length 6 and so conceptually this is what i have before i run into a wall of compiler errors. can someone please help me finish it? update: I need to reference the array and call it in the main method im trying to do so in a system.out.println statement however i dont know how to call the proper method/array.

import java.io.*;
import java.util.Arrays; 

public class SecondHighest{
 public static int find2ndHighest(int[] list){
//define how long the array can be
list[] = new int[6];
    //create a for loop to fill the array.
for(int i = 0; i>=list.length; i++){
  list[i] = (int)(Math.random()*10);

}
  Arrays.sort(list);    //use the built-in sorting routine
  return list[1];

}
}

Answer 1

your loop would never work as i would never be greater than or equal to list.length

change

for(int i = 0; i>=list.length; i++){

to

for(int i = 0; i<list.length; i++){

it should be less than because, Array indexes start from zero and end at Arraylength-1 .

also change

list[] = new int[6];// this is wrong 

 to 

list = new int[6]; // you dont need sqare brackets, you only need array reference.

Answer 2

Read your compiler errors! There are many syntax errors, like calling list -> list[] after you got it as a parameter. You can just call it list! Furthermore you don't have to create a new list inside your method! Should be something like this:

 import java.io.*;
    import java.util.Arrays; 

    public class SecondHighest{

     public static int find2ndHighest(int[] list){

        //create a for loop to fill the array.
    for(int i = 0; i<list.length; i++){
      list[i] = (int)(Math.random()*10);

    }
      Arrays.sort(list);    //use the built-in sorting routine
      return list[1];
    }

     //define how long the array can be
      int[] list = new int[6];
      int result = find2ndHighest(list);

    }

I'm not sure with the Math random function..

Answer 3

另外，考虑到这是一个家庭作业问题，最好不要对整个数组进行排序，因为这样会得到O（n * logn）复杂度，但是要遍历值并仅保留最大的两个值（n）复杂性。