The printf function can be used to print any number of arguments.
The template string argument you supply in a call provides
information not only about the number of additional arguments, but also
about their types and what style should be used for printing them.
Ordinary characters in the template string are simply written to the
output stream as-is, while conversion specifications introduced by
a `%' character in the template cause subsequent arguments to be
formatted and written to the output stream. For example,
int pct = 37;
char filename = "foo.txt";
printf ("Processing of `%s' is %d%% finished.\nPlease be patient.\n",
produces output like
Processing of `foo.txt' is 37% finished.
Please be patient.
This example shows the use of the `%d' conversion to specify that
an int argument should be printed in decimal notation, the
`%s' conversion to specify printing of a string argument, and
the `%%' conversion to print a literal `%' character.
There are also conversions for printing an integer argument as an
unsigned value in octal, decimal, or hexadecimal radix (`%o',
`%u', or `%x', respectively); or as a character value
Floating-point numbers can be printed in normal, fixed-point notation
using the `%f' conversion or in exponential notation using the
`%e' conversion. The `%g' conversion uses either `%e'
or `%f' format, depending on what is more appropriate for the
magnitude of the particular number.
You can control formatting more precisely by writing modifiers
between the `%' and the character that indicates which conversion
to apply. These slightly alter the ordinary behavior of the conversion.
For example, most conversion specifications permit you to specify a
minimum field width and a flag indicating whether you want the result
left- or right-justified within the field.
The specific flags and modifiers that are permitted and their
interpretation vary depending on the particular conversion. They're all
described in more detail in the following sections. Don't worry if this
all seems excessively complicated at first; you can almost always get
reasonable free-format output without using any of the modifiers at all.
The modifiers are mostly used to make the output look “prettier” in
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