背诵和提示输出对齐C++，输出格式

Question

我正在为我的编程课编写这段代码，我让其他一切都可以工作，但我的输出格式不适合我。

#include <iostream>
#include <iomanip>
#include <ios>
using namespace std;
int main()
{
double tip_fifteen;
double tip_twenty;
double tax;
double bill;
char dollars = '$';
float meal_cost;
cout << "Enter the meal cost: ";
cin >> meal_cost;
tip_twenty = meal_cost * .20;
tip_fifteen = meal_cost * .15;
tax = meal_cost * 0.0975;
cout << "******************************************" << endl;
//beginning outputs
int digits;
digits = meal_cost * 100 / 100;
cout << setw(10) << left << "Meal Cost " << dollars;
cout << setw(to_string(digits).length() + 3) << fixed << showpoint << setprecision(2) << meal_cost << endl;
cout << setw(10) << left << "Tax " << dollars;
cout << setw(to_string(digits).length() + 3) << fixed << showpoint << setprecision(2) << tax << endl;
cout << setw(10) << left << "Tip (15%) " << dollars;
cout << setw(to_string(digits).length() + 3) << fixed << showpoint << setprecision(2) << tip_fifteen << endl;
//tip outputs then final output statements
cout << setw(10) << left << fixed << setprecision(2) << "Tip (20%) " << dollars << tip_twenty << endl;
bill = tip_fifteen + meal_cost + tax;
cout << "Your total bill is " << fixed << setprecision(2) << dollars << bill << " after 15% gratuity." << endl << "or" << endl;
bill = tip_twenty + meal_cost + tax;
cout << "Your total bill is " << fixed << setprecision(2) << dollars << bill << " after 20% gratuity." << endl;

return 0;

我希望我的输出看起来像这样

Enter the meal cost: 56
******************************************
Meal Cost $ 56.00
Tax       $  5.46
Tip (15%) $  8.40
Tip (20%) $ 11.20
Your total bill is 69.86 after 15% gratuity.
or
Your total bill is 72.66 after 20% gratuity.

我的输出如下所示

Enter the meal cost: 56
******************************************
Meal Cost $56.00
Tax       $5.46 
Tip (15%) $8.40 
Tip (20%) $11.20
Your total bill is $69.86 after 15% gratuity.
or
Your total bill is $72.66 after 20% gratuity.

我在使用带有浮点数的 setw 时遇到问题，但是当我尝试将相同的变量设置为 int 时，它不起作用。 我还尝试使用 setw(25) 看看它是否会以某种方式工作，不幸的是它没有

Answer 1

如果你想让它们向右对齐，你需要使用right，你还需要在dollars后添加一个空格" ">

cout << setw(10) << left << "Meal Cost " << dollars << " ";
cout << setw(to_string(digits).length() + 3) << fixed << right << showpoint << setprecision(2) << meal_cost << endl;

对于所有打印的报表，您将获得：

******************************************
Meal Cost $ 56.00
Tax       $  5.46
Tip (15%) $  8.40
Tip (20%) $ 11.20

Answer 2

要在价格列中有填充，setw必须设置为足够大的宽度。

例如：

std::cout << "$" << std::setw(10) << std::fixed
<< std::setprecision(2) << 56.0f << std::endl;

指纹：

$     56.00

代码将宽度设置为：

std::to_string(digits).length() + 3

只有 5 个字符，刚好适合"56.00"。对于左侧的其他填充，您应该增加setw宽度。