calc/help/printf

NAME
    printf - formatted print to standard output

SYNOPSIS
    printf(fmt, x_1, x_2, ...)

TYPES
    fmt			string
    x_1, x_2, ...	any

    return		null

DESCRIPTION
    The function printf() is similar to the C function with the same name.
    The most significant difference is that there is no requirement
    that the types of values of the arguments x_i match the
    corresponding format specifier in fmt.  Thus, whatver the
    format specifier, a number is printed as a number, a string as
    a string, a list as a list, a matrix as a matrix, an xx-object
    as an xx-object, etc.

    Except when a '%' is encountered, characters of the string fmt are
    printed in succession to the standard output.  Occurrence of
    a '%' indicates the intention to build a format specifier.
    This is completed by a succession of characters as follows:

	    an optional '-'
	    zero or more decimal digits
	    an optional '. followed by zero or more decimal deigits
	    an optional 'l'
	    one of the letters: d, s, c, f, e, r, o, x, b,

    If any other character is read, the '%' and any characters
    between '%' and the character are ignored and no specifier is
    formed.  E.g. "%+f" prints as if only "f" were read; "% 10s"
    prints as "10s", "%X" prints as "X", "%%" prints as "%".

    The characters in a format specifier are interpreted as follows:

	    a minus sign sets the right-pad flag;
	    the first group of digits determines the width w;
		    w = 0 if there are no digits
	    a dot indicates the precision is to be read from the
		    following digits; if there is no dot,
		    precision = config("display").
	    any digits following the . determines the precision p;
		    p = 0 if there are no digits
	    any 'l' before the final letter is ignored
	    the final letter determines the mode as follows:

	    d, s, c		current config("mode")
	    f		real (decimal, floating point)
	    e		exponential
	    r		fractional
	    o		octal
	    x		hexadecimal
	    b		binary

    If the number of arguments after fmt is less than the
    number of format specifiers in fmt, the "missing" arguments
    may be taken to be null values - these contribute nothing to the
    output; if a positive width w has been specified, the effect is
    to produce w spaces, e.g. printf("abc%6dxyz") prints "abc	   xyz".

    If i <= the number of specifiers in fmt, the value of argument x_i
    is printed in the format specified by the i-th specifier.
    If a positive width w has been specified and normal printing of x_i
    does not include a '\n' character, what is printed will if necessary
    be padded with spaces so that the length of the printed output
    is at least the w.	Note that control
    characters like '\t', '\b' each count as one character.  If
    the 'right-pad' flag has been set, the padding is on the right;
    otherwise it is on the left.

    If i > the number of specifiers in fmt, the value of argument x_i
    does not contribute to the printing.  However, as all arguments
    are evaluated before printing occurs, side-effects of the
    evaluation of x_i might affect the result.

    If the i-th specifier is of numerical type, any numbers in the
    printing of x_i will be printed in the specified format, unless
    this is modified by the printing procedure for x_i's type.	Any
    specified precision will be ignored except for floating-point
    mode.

    In the case of floating-point (f) format the precision determines
    the maximum number of decimal places to be
    displayed.	Other aspects of this printing may be affected by the
    configuration parameters "outround", "tilde", "fullzero", "leadzero".

EXAMPLE
    > c = config("epsilon", 1e-6); c = config("display", 6);
    > c = config("tilde", 1); c = config("outround", 0);
    > c = config("fullzero", 0);
    > fmt = "%f,%10f,%-10f,%10.4f,%.4f,%.f.\n";
    > a = sqrt(3);
    > printf(fmt,a,a,a,a,a,a);
    1.732051,  1.732051,1.732051  ,   ~1.7320,~1.7320,~1.

    > c = config("tilde", 0); c = config("outround",24);
    > c = config("fullzero", 1);
    > printf(fmt,a,a,a,a,a,a);
    1.732051,  1.732051,1.732051  ,    1.7321,1.7321,2.

    > mat A[4] = {sqrt(2), 3/7, "undefined", null()};
    > printf("%f%r",A,A);
    mat [4] (4 elements, 4 nonzero):
      [0] = 1.414214
      [1] = .428571
      [2] = "undefined"
      [3] = NULL

    mat [4] (4 elements, 4 nonzero):
      [0] = 707107/500000
      [1] = 3/7
      [2] = "undefined"
      [3] = NULL


LIMITS
    The number of arguments of printf() is not to exceed 100.

LIBRARY
    none

SEE ALSO
    fprintf, strprintf, print