Java:整数除法舍入

Question

我正在尝试编写一个程序，提示用户输入旅馆的总楼层数、每层的房间数以及已入住的房间数。最后，它应该显示房间总数、已占用房间总数以及已占用房间的百分比。我在显示房间占用百分比时遇到问题。我正在使用所有 int 数字。

这是我提出的等式:

roomsOccPercentage = (totalRoomsOccupied * 100) / totalRooms ;

当我将程序提交到教授的 Java 运行程序时，它显示:

65 % of the Rooms are occupied.

但是我的教授提供的答案输出了 66%，所以程序不会接受我的文件。

有谁知道我做错了什么？是 DecimalFormat 错误吗？

编辑:这是整个代码

import java.util.Scanner; 
import java.text.DecimalFormat;

public class hw7_1 {
    public static void main(String[]args) {

        Scanner keyboard = new Scanner(System.in);
        DecimalFormat formatter = new DecimalFormat("#0");
        int totalFloors;
        int totalRooms = 0;
        int numFloors;
        int numRooms;
        int roomsOccupied;
        int totalRoomsOccupied = 0;
        int roomsOccPercentage = 0;

        //prompting users to input # of floors, no inputs below 1 floor
        do {
            System.out.println("Please enter the number of floors in the hotel: ");
            numFloors = keyboard.nextInt();

            if (numFloors < 1) {
                System.out.println("You have entered an invalid number of floors. ");
            }
        }
        while (numFloors < 1);

        //for loops on how many rooms on each hotel floors
        for ( int Floors = 1; Floors <= numFloors; Floors++) {
            if (Floors == 13 ) {
                continue;
            }

            do {
                System.out.println("Please enter the number of rooms on floor #: " + Floors );
                numRooms = keyboard.nextInt();

                if (numRooms < 10) {
                    System.out.println("You have entered an invalid number of rooms. ");
                }
            } while (numRooms < 10);

            System.out.println("Please enter the number of occupied rooms on floor #: " + Floors);
            roomsOccupied = keyboard.nextInt();

            totalRooms = totalRooms + numRooms;
            totalRoomsOccupied = totalRoomsOccupied + roomsOccupied;
            roomsOccPercentage = (totalRoomsOccupied * 100) / totalRooms ;
        }
        System.out.println("\nThe hotel has a total of " + totalRooms + " rooms.");
        System.out.println(totalRoomsOccupied + " of the rooms are occupied.");
        System.out.println(formatter.format(roomsOccPercentage) + "% of the rooms are occupied.");
    }
}

Answer 1

注意java有它自己的规则，你需要遵守它们。决定你是想要结果的 floor 还是 ceil，按照下面给出的例子。

double roomsOccPercentage;
roomsOccPercentage =Math.ceil((double)5/4); //will be 2
roomsOccPercentage =Math.ceil(5/4); //will be 1
roomsOccPercentage =Math.floor((double)5/4); //will be 1

我希望你现在能对 java 感兴趣