The meaning of the precision for the various format types is as follows:
e, E, f
the number of digits to be printed after the decimal point.
the number of significant digits to be printed.
the number of significant digits to be printed for each of the real and imaginary parts of the value.
d, i, o, u, x, X
the minimum number of digits to be printed (padded with whitespace,
except when the
0 modifier is used, which yields padding with
the maximum number of string characters to be printed.
the number of sexagesimal elements to print.