使用二分查找法在数组中查找关键字key

Question

Java软件里写代码，使用二分查找法在数组中查找关键字key。

Answer 1

直接看java.util.Arrays中的源码

package Account_system;

import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class Answer1 {

    public static void main(String[] args) {
        int a[] = new int[100];
        for (int i = 0; i < a.length; i++) {
            a[i] = new Random().nextInt(100)+1;
        }
        System.out.println("输入要查找的key");
        Arrays.sort(a);
        System.out.println(Arrays.toString(a));
        int key = new Scanner(System.in).nextInt();
        int index = Arrays.binarySearch(a, key);

        System.out.println("index=" + index);

    }

}