function r = s_to_r ( s )
%% S_TO_R reads a real number from a string.
%
%
% Discussion:
%
% This routine will read as many characters as possible until it reaches
% the end of the string, or encounters a character which cannot be
% part of the real number.
%
% Legal input is:
%
% 1 blanks,
% 2 '+' or '-' sign,
% 2.5 spaces
% 3 integer part,
% 4 decimal point,
% 5 fraction part,
% 6 'E' or 'e' or 'D' or 'd', exponent marker,
% 7 exponent sign,
% 8 exponent integer part,
% 9 exponent decimal point,
% 10 exponent fraction part,
% 11 blanks,
% 12 final comma or semicolon.
%
% with most quantities optional.
%
% Examples:
%
% S R
%
% '1' 1.0
% ' 1 ' 1.0
% '1A' 1.0
% '12,34,56' 12.0
% ' 34 7' 34.0
% '-1E2ABCD' -100.0
% '-1X2ABCD' -1.0
% ' 2E-1' 0.2
% '23.45' 23.45
% '-4.2E+2' -420.0
% '17d2' 1700.0
% '-14e-2' -0.14
% 'e2' 100.0
% '-12.73e-9.23' -12.73 * 10.0**(-9.23)
%
% Modified:
%
% 22 November 2003
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, character ( len = * ) S, the string containing the
% data to be read. Reading will begin at position 1 and
% terminate at the end of the string, or when no more
% characters can be read to form a legal real. Blanks,
% commas, or other nonnumeric data will, in particular,
% cause the conversion to halt.
%
% Output, real R, the real value that was read from the string.
%
s_length = s_len_trim ( s );
ierror = 0;
r = 0.0E+00;
r_length = -1;
isgn = 1;
rtop = 0.0E+00;
rbot = 1.0E+00;
jsgn = 1;
jtop = 0;
jbot = 1;
ihave = 1;
iterm = 0;
while ( 1 )
r_length = r_length + 1;
c = s(r_length+1);
%
% Blank character.
%
if ( c == ' ' )
if ( ihave == 2 )
elseif ( ihave == 6 | ihave == 7 )
iterm = 1;
elseif ( 1 < ihave )
ihave = 11;
end
%
% Comma.
%
elseif ( c == ',' | c == ';' )
if ( ihave ~= 1 )
iterm = 1;
ihave = 12;
r_length = r_length + 1;
end
%
% Minus sign.
%
elseif ( c == '-' )
if ( ihave == 1 );
ihave = 2;
isgn = -1;
elseif ( ihave == 6 )
ihave = 7;
jsgn = -1;
else
iterm = 1;
end
%
% Plus sign.
%
elseif ( c == '+' )
if ( ihave == 1 )
ihave = 2;
elseif ( ihave == 6 )
ihave = 7;
else
iterm = 1;
end
%
% Decimal point.
%
elseif ( c == '.' )
if ( ihave < 4 )
ihave = 4;
elseif ( 6 ihave = 9;
else
iterm = 1;
end
%
% Exponent marker.
%
elseif ( ch_eqi ( c, 'E' ) | ch_eqi ( c, 'D' ) )
if ( ihave < 6 )
ihave = 6;
else
iterm = 1;
end
%
% Digit.
%
elseif ( ihave < 11 & ch_is_digit ( c ) )
if ( ihave ihave = 3;
elseif ( ihave == 4 )
ihave = 5;
elseif ( ihave == 6 | ihave == 7 )
ihave = 8;
elseif ( ihave == 9 )
ihave = 10;
end
d = ch_to_digit ( c );
if ( ihave == 3 )
rtop = 10.0E+00 * rtop + d;
elseif ( ihave == 5 )
rtop = 10.0E+00 * rtop + d;
rbot = 10.0E+00 * rbot;
elseif ( ihave == 8 )
jtop = 10 * jtop + d;
elseif ( ihave == 10 )
jtop = 10 * jtop + d;
jbot = 10 * jbot;
end
%
% Anything else is regarded as a terminator.
%
else
iterm = 1;
end
%
% If we haven't seen a terminator, and we haven't examined the
% entire string, go get the next character.
%
if ( iterm == 1 | s_length break;
end
end
%
% If we haven't seen a terminator, and we have examined the
% entire string, then we're done, and R_LENGTH is equal to S_LENGTH.
%
if ( iterm ~= 1 & r_length + 1 == s_length )
r_length = s_length;
end
%
% Number seems to have terminated. Have we got a legal number?
% Not if we terminated in states 1, 2, 6 or 7!
%
if ( ihave == 1 | ihave == 2 | ihave == 6 | ihave == 7 )
ierror = ihave;
fprintf ( 1, '\n' );
fprintf ( 1, 'S_TO_R - Fatal error!\n' );
fprintf ( 1, ' IHAVE = %d\n', ihave );
error ( 'S_TO_R - Fatal error!' );
end
%
% Number seems OK. Form it.
%
if ( jtop == 0 )
rexp = 1.0E+00;
else
if ( jbot == 1 )
rexp = 10.0E+00.^( jsgn * jtop );
else
rexp = jsgn * jtop;
rexp = rexp / jbot;
rexp = 10.0E+00.^rexp;
end
end
r = isgn * rexp * rtop / rbot;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function len = s_len_trim ( s )
% S_LEN_TRIM returns the length of a character string to the last nonblank.
%
% Modified:
%
% 14 June 2003
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, string S, the string to be measured.
%
% Output, integer LENGTH, the length of the string up to the last nonblank.
%
len = length ( s );
while ( 0 < len )
if ( s(len) ~= ' ' )
return
end
len = len - 1;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function truefalse = ch_eqi ( c1, c2 )
%% CH_EQI is a case insensitive comparison of two characters for equality.
%
% Examples:
%
% CH_EQI ( 'A', 'a' ) is TRUE.
%
% Modified:
%
% 28 July 2000
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, character C1, C2, the characters to compare.
%
% Output, logical TRUEFALSE, is TRUE (1) if the characters are equal.
%
FALSE = 0;
TRUE = 1;
if ( ch_cap ( c1 ) == ch_cap ( c2 ) )
truefalse = TRUE;
else
truefalse = FALSE;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function c2 = ch_cap ( c )
%% CH_CAP capitalizes a single character.
%
% Modified:
%
% 22 November 2003
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, character C, the character to capitalize.
%
% Output, character C2, the capitalized character.
%
if ( 'a' c2 = c + 'A' - 'a';
else
c2 = c;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function truefalse = ch_is_digit ( c )
% CH_IS_DIGIT returns TRUE if the character C is a digit.
%
% Modified:
%
% 11 December 2003
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, character C, a character.
%
% Output, integer TRUEFALSE, is TRUE (1) if C is a digit, FALSE (0) otherwise.
%
TRUE = 1;
FALSE = 0;
if ( '0' truefalse = TRUE;
else
truefalse = FALSE;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function digit = ch_to_digit ( c )
%% CH_TO_DIGIT returns the integer value of a base 10 digit.
%
% Example:
%
% C DIGIT
% --- -----
% '0' 0
% '1' 1
% ... ...
% '9' 9
% ' ' 0
% 'X' -1
%
% Modified:
%
% 22 November 2003
%
% Author:
%
% John Burkardt
%
% Parameters:
%
% Input, character C, the decimal digit, '0' through '9' or blank
% are legal.
%
% Output, integer DIGIT, the corresponding integer value. If C was
% 'illegal', then DIGIT is -1.
%
if ( '0'
digit = c - '0';
elseif ( c == ' ' )
digit = 0;
else
digit = -1;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
