Question

假设我想打印像这张桌子一样简单的东西：

January   1
February  2
March     3
April     4
May       5
June      6
July      7
August    8
September 9
October   10
November  11
December  12

我想这样做：

for(tm i{ 0, 0, 0, 1, 0 }; i.tm_mon < 12; ++i.tm_mon) cout << put_time(&i, "%-9B") << i.tm_mon + 1 << endl;

不幸的是puttime似乎不允许我在其格式字段中使用字段标志。此外，此puttime似乎与setw无关。

我唯一的选择是strftime，然后将其用于setw？

Answer 1

The following will also work

for(tm i{ 0, 0, 0, 1, 0 }; i.tm_mon < 12; ++i.tm_mon)
    {
        std::stringstream oss;
        oss << std::put_time(&i, "%B");
        string str = oss.str();
        cout << std::setiosflags(std::ios::left) << setw( 10 )  << str << setw( 2 ) << i.tm_mon + 1 << endl;
    }

Answer 2

这是一个尊重I / O操纵器的header-only library：

#include "date.h"
#include <iomanip>
#include <iostream>

int
main()
{
    using namespace date;
    using namespace std;
    auto m = jan;
    do
    {
        cout << left << setw(10) << format("%B", sys_days{m/1/1}) << right
             << unsigned(m) << '\n';
    } while (++m != jan);
}

您可以将上述代码粘贴到此wandbox link。

中自行尝试

January   1
February  2
March     3
April     4
May       5
June      6
July      7
August    8
September 9
October   10
November  11
December  12

如何在puttime中格式化宽度？

2 个答案: