For example, a (%02d) in a format string for printf is a placeholder for an integer variable that will be printed in decimal (%02d) and padded to at least two digits, with zeros if necessary. The actual integer is supplied by you in an an argument to the function, e.g. printf("%02d",5); would print 05 on screen, (%01d) also works similarly

2016年4月11日 · 02d formats an integer (d) to a field of minimum width 2 (2), with zero-padding on the left (leading 0 ...

2015年11月1日 · In this question when we are talking about %d we are talking about the hours, the : is the : on digital clocks, and by the %02d we mean the minutes padded down with 0s on the left side up to two digits.

I want to output an integer to a std::stringstream with the equivalent format of printf's %02d. Is there an easier way to achieve this than: std::stringstream stream; stream.setfill('0'); stream.setw(2); stream << value; Is it possible to stream some sort of format flags to the stringstream, something like (pseudocode):

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Keep in mind that the %02d means two characters minimum width so it would output 123 as 123. That shouldn't be a problem if your values are valid hours, minutes and seconds, but it's worth keeping in mind because many inexperienced coders seem to make the mistake that 2 is somehow the minimum and maximum length.

All of these create the string "01": >python -m timeit "'{:02d}'.format(1)" 1000000 loops, best of 5: 357 nsec per loop >python -m timeit "'{0:0{1}d}'.format(1,2)" 500000 loops, best of 5: 607 nsec per loop >python -m timeit "f'{1:02d}'" 1000000 loops, best of 5: 281 nsec per loop >python -m timeit "f'{1:0{2}d}'" 500000 loops, best of 5: 423 nsec per loop >python -m timeit "str(1).zfill(2 ...

2021年1月22日 · %02d means a decimal integer where its number of digits is less than two, it will be zero-padded. Otherwise, just print it because the given width 2 means the number of minimum characters to print including zeros, spaces, and digits.

Given that the formatting operator is specifying %02d, just like it does in the first if branch (which behaves as expected), why is it not obeying in the second branch? I'm at a loss trying to figure out why it is still printing the full result rather than the truncated version.

2015年8月10日 · The > is redundant here, because 02d would already right-align. It'd be different if a larger field width was picked, though, because 02d is effectively the same as 0=2d, meaning that the 0 padding is placed between the sign and the value, while 0>2d places the padding before the sign. But with a field width of 2 even a single-digit negative ...