C++ 如何在puttime中设置宽度格式？

假设我想打印一些简单的东西，如下表：

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

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;

---

对于（tm i{0,0,0,1,0}；i.tm_-mon<12；++i.tm_-mon）cout而言，以下操作也将起作用

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;
    }

for（tm i{0,0,0,1,0}；i.tm_-mon<12；++i.tm_-mon）
{
std：：stringstream-oss；
oss以下功能也将起作用

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;
    }

for（tm i{0,0,0,1,0}；i.tm_-mon<12；++i.tm_-mon）
{
std：：stringstream-oss；
oss下面是一个关于I/O操纵器的示例：

#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);
}

下面是一个关于I/O操纵器的示例：

#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);
}