void lx4num_c ( ConstSpiceChar * string,
SpiceInt * last,
SpiceInt * nchar )
Scan a string from a specified starting position for the
end of a number.
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
string I Any character string.
first I First character to scan from in string.
last O Last character that is part of a number.
nchar O Number of characters in the number.
string is any character string.
first is the location in the string to beginning scanning
for a number. It is assumed that the
number begins at first.
The normal range of first is 0 : strlen(string)-1.
last is the last character at or after first such that the
substring ranging from string[first] through
string[last] is a number. If there is no such
substring, last will be returned with the value first-1.
If a number is found, last will be in the
range is 0 : strlen(string)-1.
nchar is the number of characters in the number that
begins at index first and ends at last. If there is no
such string nchar will be given the value 0.
1) If first is beyond either end of the string, then
last will be returned with the value first-1 and nchar
will be returned with the value 0.
2) If string[first] is not part of a number then last
will be returned with the value first-1 and nchar will be
returned with the value 0.
3) If the input string pointer is null, the error SPICE(NULLPOINTER)
will be signaled.
4) If the input string has length zero, last will be set to first-1
and nchar will be set to zero. This case is not considered an
This routine allows you to scan forward in a string to locate a
number that begins on the input character first. Note that all
decimal numbers are included in the list of numbers. The main
difference between decimal numbers and numbers is that numbers may
have an exponential expression attached (i.e. the exponent character
'e','E','d' or 'D' followed by an signed integer).
1) Suppose you believe that a string has the form
where X, Y, and Z are numbers of some unknown length and
% stands for any character that cannot occur in a number.
You could use this routine to locate the numbers in the
string as shown below. We'll keep track of the beginning and
ending of the numbers in the integer arrays b and e.
first = 0;
i = 0;
len = strlen(string);
while ( first < len-1 )
lx4num_c ( string, first, &last, &nchar );
if ( nchar > 0 )
b[i] = first;
e[i] = last;
first = last + 2;
N.J. Bachman (JPL)
W.L. Taber (JPL)
-CSPICE Version 1.0.0, 18-AUG-2002 (NJB) (WLT)
Scan a string for a number.