Java怎么用for循环给数组赋值？

Question

package les9;

import java.util.Scanner;

public class Book {

/**
 * @param args
 */
private static int bookNum;
private static double price;
public Book(int bookNum,double price){
    this.bookNum=bookNum;
    this.price=price;
}

public static double MaxPrice(Book[] b){
    double MaxPrice=Double.MIN_VALUE;
    for(int i=0;i<b.length;i++){
        if(b[i].bookNum*b[i].price>MaxPrice){
            MaxPrice=b[i].bookNum*b[i].price;
        }
    }
    return MaxPrice;
}

public static double MinPrice(Book[] b){
    double MinPrice=Double.MAX_VALUE;
    for(int i=0;i<b.length;i++){
        if(b[i].bookNum*b[i].price<MinPrice){
            MinPrice=b[i].bookNum*b[i].price;
        }
    }
    return MinPrice;
}

public static void show() {
    System.out.println("数量:"+bookNum+"\t单价:"+price);
}

public static void showAll(Book[] b) {
    for(int i=0;i<b.length;i++) {
        System.out.println("数量:"+b[i].bookNum+"\t单价:"+b[i].price);
    }
}
public static void main(String[] args) {
    Book b[]=new Book[2];
    Scanner sc=new Scanner(System.in);
    for(int i=0;i<b.length;i++){
        System.out.println("请输入第"+(i+1)+"本书的单价:");
        int num=sc.nextInt();
        System.out.println("请输入第"+(i+1)+"本书的数量:");
        double pri=sc.nextDouble();
        b[i]=new Book(num,pri);
        Book.show();
    }
    showAll(b);
    System.out.println("最低价为:"+Book.MinPrice(b));
    System.out.println("最高价为:"+Book.MaxPrice(b));
}

}

代码如图，主要的问题是，如何在new一个对象的前提下，对数组进行循环赋值，并且能够输出前一轮循环赋值的数据

Answer 1

private static int bookNum;
private static double price;
这些不能是static的
包括 public static void show()
你首先应该把主程序和Book类分开写

package les9;

import java.util.Scanner;

class Book {

/**
 * @param args
 */
private int bookNum;
private double price;
public Book(int bookNum,double price){
    this.bookNum=bookNum;
    this.price=price;
}

public static double MaxPrice(Book[] b){
    double MaxPrice=Double.MIN_VALUE;
    for(int i=0;i<b.length;i++){
        if(b[i].bookNum*b[i].price>MaxPrice){
            MaxPrice=b[i].bookNum*b[i].price;
        }
    }
    return MaxPrice;
}

public static double MinPrice(Book[] b){
    double MinPrice=Double.MAX_VALUE;
    for(int i=0;i<b.length;i++){
        if(b[i].bookNum*b[i].price<MinPrice){
            MinPrice=b[i].bookNum*b[i].price;
        }
    }
    return MinPrice;
}

public void show() {
    System.out.println("数量:"+bookNum+"\t单价:"+price);
}

public static void showAll(Book[] b) {
    for(int i=0;i<b.length;i++) {
        System.out.println("数量:"+b[i].bookNum+"\t单价:"+b[i].price);
    }
}
}
public class Program {
public static void main(String[] args) {
    Book b[]=new Book[2];
    Scanner sc=new Scanner(System.in);
    for(int i=0;i<b.length;i++){
        System.out.println("请输入第"+(i+1)+"本书的单价:");
        int num=sc.nextInt();
        System.out.println("请输入第"+(i+1)+"本书的数量:");
        double pri=sc.nextDouble();
        b[i]=new Book(num,pri);
        b[i].show();
    }
    Book.showAll(b);
    System.out.println("最低价为:"+Book.MinPrice(b));
    System.out.println("最高价为:"+Book.MaxPrice(b));
}
}

将Book.java重命名为Program.java