JAVA基础之题目练习

0x01

编写类A01，定义方法max，实现求某个double数组的最大值，并返回Homework01.java

public class Homework01 {
    public static void main(String[] args){
        double[] numbers = {534, 1,34, 90, 56.9, 23, 45, 103.981};
        A01 a01 = new A01();
        System.out.println("The max number is " + a01.max(numbers));;
    }
}


class A01{
    public double max(double[] number){
        double maxnum = number[0];
        int i = 0;
        for(; i  number[i] ? maxnum : number[i];
        }

        return maxnum;
    }
}

The max number is 534.0

0x02

编写类A02，定义方法find，实现查找某字符串数组中的元素查找，并返回索引，如果找不到，返回-1。

public class Homework02 {
    public static void main(String[] args){
        String[] data = {"hello", "hi", "yes", "no"};
        String finddata = "yes";
        A02 a02 = new A02();
        int index = a02.find(data, finddata);
        if(index == -1){
            System.out.println("NoFind, the index is " + index);
        }else {
            System.out.println("Find, the index is " + index);
        }
    }
}

class A02{
    public int find(String[] data, String finddata){
        int i = 0;
        for(; i 150，则更改为150，如果价格>100，更改为100，否则不变。
 
 
public class Homework03 {
    public static void main(String[] args){
        book bo = new book("xiyouji", 102.4);
        bo.updatePrice();
    }
}

class book{

    String name;
    double price;

    public book(String name, double price){
        this.name = name;
        this.price = price;
    }
    public void updatePrice(){
        if(price > 150){
            price = 150;
        }else if(price > 100){
            price = 100;
        }
        System.out.println("The book name is " + name + ";price is " + price);
    }
}

The book name is xiyouji;price is 100.0
 
0x04 
 
 
编写类A03，实现数组的复制功能copyArr，输入旧数组，返回一个新数组，元素和旧数组一样。
 
 
public class Homework04 {
    public static void main(String[] args){
        A03 a03 = new A03();
        int[] arrOld = {1,2,3,9,8,7};
        int[] arrNew = a03.copyArr(arrOld);
        for (int i = 0; i