< library > The standard function in the C programming language library for printing formatted output.
The first argument is a format string which may contain ordinary characters which are just printed and "conversion specifications" - sequences beginning with '%' such as %6d which describe how the other arguments should be printed, in this case as a six-character decimal integer padded on the right with spaces.
Possible conversion specifications are d, i or u (decimal integer), o ( octal ), x, X or p ( hexadecimal ), f ( floating-point ), e or E ( mantissa and exponent , e.g. 1.23E-22), g or G (f or e format as appropriate to the value printed), c (a single character), s (a string), % (i.e. %% - print a % character). d, i, f, e, g are signed, the rest are unsigned.
The variant fprintf prints to a given output stream and sprintf stores what would be printed in a string variable.
Unix manual page : printf(3).
(1996-12-08)