mirror of
https://github.com/lcn2/calc.git
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81a4a4f828
Updated the help files help/config, help/display, help/epsilon,
help/fprint, help/printf, and help/strprintf to give more
examples of how display digits and epsilon precision interact
with displaying values.
Added more information about %g in the help file help/printf.
The '\a' is now recognized in a printf format string as the
single byte audible bell character (byte 0x07 in ASCII encoding).
The following is a partial list of escape sequences recognized
in strings and in printf formats:
\a audible bell byte 0x07 in ASCII encoding
\b backspace byte 0x08 in ASCII encoding
\f form feed byte 0x0c in ASCII encoding
\n newline byte 0x0b in ASCII encoding
\r return byte 0x0a in ASCII encoding
\t tab byte 0x0d in ASCII encoding
\v vertical tab byte 0x09 in ASCII encoding
255 lines
9.2 KiB
Plaintext
255 lines
9.2 KiB
Plaintext
NAME
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printf - formatted print to standard output
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SYNOPSIS
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printf(fmt, x_1, x_2, ...)
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TYPES
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fmt string
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x_1, x_2, ... any
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return null
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DESCRIPTION
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The function printf() is similar to the C function with the same name.
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The most significant difference is that there is no requirement
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that the types of values of the arguments x_i match the
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corresponding format specifier in fmt. Thus, whatver the
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format specifier, a number is printed as a number, a string as
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a string, a list as a list, a matrix as a matrix, an xx-object
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as an xx-object, etc.
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Except when a '%' is encountered, characters of the string fmt are
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printed in succession to the standard output. Occurrence of
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a '%' indicates the intention to build a format specifier.
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This is completed by a succession of characters as follows:
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an optional '-'
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zero or more decimal digits
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an optional '. followed by zero or more decimal deigits
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an optional 'l'
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one of the letters: d, s, c, f, e, g, r, o, x, b,
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If any other character is read, the '%' and any characters
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between '%' and the character are ignored and no specifier is
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formed. E.g. "%+f" prints as if only "f" were read; "% 10s"
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prints as "10s", "%X" prints as "X", "%%" prints as "%".
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The characters in a format specifier are interpreted as follows:
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a minus sign sets the right-pad flag;
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the first group of digits determines the width w;
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w = 0 if there are no digits
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a dot indicates the precision is to be read from the
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following digits; if there is no dot,
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precision = config("display").
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any digits following the . determines the precision p;
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p = 0 if there are no digits
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any 'l' before the final letter is ignored
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the final letter determines the mode as follows:
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d, s, c current config("mode")
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f real (decimal, floating point)
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e exponential
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g general format (real or exponential)
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r fractional
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o octal
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x hexadecimal
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b binary
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If the number of arguments after fmt is less than the number
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of format specifiers in fmt, the "missing" arguments may be
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taken to be null values - these contribute nothing to the output;
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if a positive width w has been specified, the effect is to
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produce w spaces, e.g., printf("abc%6dxyz") prints "abc xyz".
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Control charters may be given in fmt by escaping them with
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the \ character. The following control charter escape
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sequences are recognized:
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\a audible bell byte 0x07 in ASCII encoding
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\b backspace byte 0x08 in ASCII encoding
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\f form feed byte 0x0c in ASCII encoding
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\n newline byte 0x0b in ASCII encoding
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\r return byte 0x0a in ASCII encoding
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\t tab byte 0x0d in ASCII encoding
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\v vertical tab byte 0x09 in ASCII encoding
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If i <= the number of specifiers in fmt, the value of argument
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x_i is printed in the format specified by the i-th specifier.
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If a positive width w has been specified and normal printing
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of x_i does not include a '\n' character, what is printed will
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if necessary be padded with spaces so that the length of the
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printed output is at least the w. Note that control characters
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(e.g., '\a', '\b', '\f', '\n', '\r', '\t', '\n') count as one
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character. If the 'right-pad' flag has been set, the padding
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is on the right; otherwise it is on the left.
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If i > the number of specifiers in fmt, the value of argument x_i
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does not contribute to the printing. However, as all arguments
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are evaluated before printing occurs, side-effects of the
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evaluation of x_i might affect the result.
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If the i-th specifier is of numerical type, any numbers in the
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printing of x_i will be printed in the specified format, unless
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this is modified by the printing procedure for x_i's type. Any
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specified precision will be ignored except for floating-point
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mode.
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The (g) general format will print the as real (f) (decimal or
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floating point) or as an exponential (e) depending on the
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configuration parameter "display".
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In the case of floating-point (f) format, and the (g) general
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format, the precision determines the maximum number of decimal
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places to be displayed. Other aspects of this printing may be
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affected by the configuration parameters "outround", "tilde",
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"fullzero", "leadzero".
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EXAMPLE
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; config("epsilon", 1e-6),;
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: config("display", 6),;
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; config("tilde", 1),;
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; config("outround", 0),;
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; config("fullzero", 0),;
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; fmt = "%f,%10f,%-10f,%10.4f,%.4f,%.f.\n";
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; a = sqrt(3);
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; printf(fmt,a,a,a,a,a,a);
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1.732051, 1.732051,1.732051 , ~1.7320,~1.7320,~1.
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; config("display", 5),;
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: config("tilde", 0),;
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; printf("%f\n", pi());
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3.1416
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; config("display", 10),;
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; printf("%f\n", pi());
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3.141592654
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; config("tilde", 0),;
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: config("outround",24),;
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; config("fullzero", 1),;
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; printf(fmt,a,a,a,a,a,a);
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1.732051, 1.732051,1.732051 , 1.7321,1.7321,2.
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; mat A[4] = {sqrt(2), 3/7, "undefined", null()};
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; printf("%f%r",A,A);
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mat [4] (4 elements, 4 nonzero):
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[0] = 1.414214
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[1] = .428571
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[2] = "undefined"
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[3] = NULL
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mat [4] (4 elements, 4 nonzero):
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[0] = 707107/500000
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[1] = 3/7
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[2] = "undefined"
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[3] = NULL
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; config("display", 50),;
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; printf("%g %g\n%g %g\n", 1e5, 1e49, 1e50, 1e500);
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100000 100000000000000000000000000000000000000000000000000
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1e50 1e500
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; config("display", 10),;
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: config("tilde", 0),;
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; printf("%f %f %f\n%f %f %f\n",
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exp(1), exp(2), exp(3), exp(4), exp(5), exp(6));
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2.7182818285 7.3890560989 20.0855369232
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54.5981500331 148.4131591026 403.4287934927
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; printf("%e %e %e\n%e %e %e\n",
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exp(1), exp(2), exp(3), exp(4), exp(5), exp(6));
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2.7182818285 7.3890560989 2.0085536923e1
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5.4598150033e1 1.4841315910e2 4.0342879349e2
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; printf("%g %g %g\n%g %g %g\n",
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exp(1), exp(2), exp(3), exp(4), exp(5), exp(6));
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2.718281828 7.389056099 20.08553692
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54.59815003 148.4131591 403.4287935
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; config("display", 10),;
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; config("tilde", 0),;
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; printf("%f %f %f\n%f %f %f\n",
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exp(20), exp(21), exp(22), exp(23), exp(24), exp(25));
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485165195.4097902780 1318815734.4832146972 3584912846.1315915617
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9744803446.2489026000 26489122129.8434722941 72004899337.3858725242`
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; printf("%e %e %e\n%e %e %e\n",
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exp(20), exp(21), exp(22), exp(23), exp(24), exp(25));
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4.8516519541e8 1.3188157345e9 3.5849128461e9
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9.7448034462e9 2.6489122130e10 7.2004899337e10
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; printf("%g %g %g\n%g %g %g\n",
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exp(20), exp(21), exp(22), exp(23), exp(24), exp(25));
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485165195.4 1318815734 3584912846
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9744803446 2.648912213e10 7.200489934e10
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; /*
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* NOTE: When displaying many digits after the decimal point
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* be sure to set display(digits) (see 'help display') to
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* large enough AND to set epsilon(eps) (see 'help epsilon')
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* small enough (or if the function has a esp argument,
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* give a eps argument that is small enough) to display
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* the value correctly.
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*/
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; config("tilde", 1),;
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; /* NOTE: display has too few digits and epsilon is not small enough */
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; display(12),;
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; printf("%f\n", pi(1e-10));
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3.1415926536
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; epsilon(1e-10),;
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; printf("%f\n", pi());
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3.1415926536
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; /* NOTE: display has too few digits yet epsilon is small enough */
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; display(12),;
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; printf("%f\n", pi(1e-72));
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~3.141592653590
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; epsilon(1e-72),;
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; printf("%f\n", pi());
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~3.141592653590
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; /* NOTE: display has enough digits but epsilon is not small enough */
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; display(72),;
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; printf("%f\n", pi(1e-10));
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3.1415926536
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; epsilon(1e-10),;
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; printf("%f\n", pi());
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3.1415926536
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/* NOTE: display has enough digits and epsilon is small enough */
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; display(72),;
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; printf("%f\n", pi(1e-72));
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3.141592653589793238462643383279502884197169399375105820974944592307816406
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; epsilon(1e-72),;
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; printf("%f\n", pi());
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3.141592653589793238462643383279502884197169399375105820974944592307816406
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LIMITS
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The number of arguments of printf() is not to exceed 1024.
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LINK LIBRARY
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none
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SEE ALSO
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config, display, epsilon, fprintf, strprintf
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## Copyright (C) 1999-2006,2018 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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##
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## Under source code control: 1996/03/12 22:50:41
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## File existed as early as: 1996
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##
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## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
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## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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