Java:整数除法

Question

我正在尝试编写一个程序,提示用户输入酒店的楼层总数,每层楼的房间数量以及占用房间的数量.最后,它应显示房间总数,占用房间总数以及占用房间的百分比.我在显示占用房间的百分比方面遇到了问题.我正在使用所有的int数字.

这是我提出的等式:

roomsOccPercentage = (totalRoomsOccupied * 100) / totalRooms ;

当我将程序提交给我教授的Java运行程序时,它会显示:

65 % of the Rooms are occupied.

但是我教授提供的那个输出了66%的答案,所以程序不接受我的文件.

有谁知道我做错了什么？它是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

请注意,java使用自己的规则,您需要遵守它们.确定您是否需要结果的楼层或天花板,请按照下面给出的示例.

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

我希望你现在可以找到java intresting

Answer 2

你需要先做roomsOccPercentage双人.

double roomsOccPercentage = 0.0;

然后转换任一个操作数,以避免整数除法.

roomsOccPercentage = (totalRoomsOccupied * 100.0) / totalRooms;

您可以使用有明确的转换像(double)totalRoomsOccupied或只是让100为100.0它是一个浮点数,从而使师太,浮点一个,而不是一个整数除法.