This section provides details about the precise syntax of conversion
specifications that can appear in a
Characters in the template string that are not part of a conversion specification are printed as-is to the output stream.
The conversion specifications in a
printf template string have
the general form:
% flags width [ . precision ] type conversion
For example, in the conversion specifier ‘%-10.8ld’, the ‘-’ is a flag, ‘10’ specifies the field width, the precision is ‘8’, the letter ‘l’ is a type modifier, and ‘d’ specifies the conversion style. (This particular type specifier says to print a numeric argument in decimal notation, with a minimum of 8 digits left-justified in a field at least 10 characters wide.)
In more detail, output conversion specifications consist of an initial ‘%’ character followed in sequence by:
You can also specify a field width of ‘*’. This means that the next argument in the argument list (before the actual value to be printed) is used as the field width. The value is rounded to the nearest integer. If the value is negative, this means to set the ‘-’ flag (see below) and to use the absolute value as the field width.
You can also specify a precision of ‘*’. This means that the next argument in the argument list (before the actual value to be printed) is used as the precision. The value must be an integer, and is ignored if it is negative.
printffunction, but is recognized to provide compatibility with the C language
The exact options that are permitted and how they are interpreted vary between the different conversion specifiers. See the descriptions of the individual conversions for information about the particular options that they use.