Question

我正在做一个关于酒店入住的项目，但我在打印double变量方面遇到了困难。我需要知道如何使用double显示setprecision变量。

#include <iostream>

using namespace std;

int main()
{
    int numfloors=0; //for number of floors
    int numrooms=0; //for number of rooms per floor
    int numoccipied=0; //for rooms that are occupied
    int TRooms=0; //for total rooms in hotel
    int TOcuppied=0; //for total rooms occupied in the hotel
    int TUnoccupied=0; //for unoccupied rooms in the hotel
    double occupancy=0; //for persentage occupancy

    cout<<"Enter the number of floors in the hotel"
        <<"\nNote: please do not write value less than 1: ";
    cin>>numfloors;

    for(int floor=1; floor<=numfloors; floor++) //loop starts
    {
        cout<<"how many rooms are there in no."<<floor<<"floor?\n"; //ask user to for number of rooms per floor
        cin>>numrooms;

        TRooms+= numrooms; //total rooms in each floor will add and store in Trooms
        cout<<"how many rooms are ocupied?\n";  //ask user to put number of occupied rooms
        cin>>numoccipied;
        TOcuppied+=numoccipied; //number of rooms occupied per floor is added 
        TUnoccupied=TRooms-TOcuppied; //stores all unoccupied rooms
        occupancy=(TOcuppied)/TRooms; //store persentage occupancy 

        cout<<"\n\nThe Hotel has "<<TRooms<<"rooms\n";
        cout<<"from which "<<TOcuppied<< " rooms are occupied,\n";
        cout<<"and "<<TUnoccupied<<" are Unoccupied.\n ";
    }
    cout << fixed << showpoint << setprecision(1);
    cout<<"\n\nOccupancy Rate: "<<occupancy*100<<"% \n\n";
    return 0;
}

Answer 1

您似乎是初学者，所以我会列出您的代码的一些问题：

分割两个整数时，结果也是整数。因此，在积分除法中，4/10为0.因此，该行总是产生零：
```
occupancy=(TOcuppied)/TRooms;
```
改为使用：
```
occupancy=(TOcuppied)/(double)TRooms;
```

cout的设置显然必须在输入之前完成。所以首先发送设置：

cout << fixed << showpoint << setprecision(1);

然后：

cout << occupancy*100;

当然，你可以把它放在一行：

cout << fixed << showpoint << setprecision(1)<< occupancy*100;

您允许某些无效输出。既然你看起来很像家庭作业，你可能需要消毒那些。一个是你允许一个人进入比可用空间更多的房间：

how many rooms are there in no.1floor?
10
how many rooms are ocupied?
20

The Hotel has 10rooms
from which 20 rooms are occupied,
and -10 are Unoccupied.

Occupancy Rate: 200.00%

所以请记住检查输入：

if(numoccipied>numrooms) {
    // do something, such as asking the user to enter correct value
}

同样，您应该阻止用户进入少于1层：

if(numfloors<1)
    return 0;

如何在for循环内部或外部打印double变量

1 个答案: