如何在 for 循环内部或外部打印双精度变量

how do i print the double variable inside or outside the for loop

本文关键字：外部打印双精度变量内部 for 循环更新时间：2023-10-16

我正在做一个关于酒店入住率的项目，但我在打印double变量时遇到困难。我需要知道如何使用 setprecision 显示double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<<"nnThe Hotel has "<<TRooms<<"roomsn";
        cout<<"from which "<<TOcuppied<< " rooms are occupied,n";
        cout<<"and "<<TUnoccupied<<" are Unoccupied.n ";
    }
    cout << fixed << showpoint << setprecision(1);
    cout<<"nnOccupancy Rate: "<<occupancy*100<<"% nn";
    return 0;
}

你似乎是一个初学者，所以我会列出你的代码的一些问题：

当除以两个整数时，结果也是一个整数。因此，在积分除法中，4/10 为 0。因此，此行始终产生零：
```
occupancy=(TOcuppied)/TRooms;
```
而是使用：
```
occupancy=(TOcuppied)/(double)TRooms;
```

cout的设置显然必须全部出现在输入之前。因此，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上：

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

您允许某些类型的无效输出。由于您的作业看起来很像家庭作业，因此您可能需要对其进行消毒。一个是你允许一个人进入比可用更多的占用房间：

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%

因此，请记住检查该输入：

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

同样，您应该防止用户进入少于 1 层：

if(numfloors<1)
    return 0;