- Abstract
Find the first occurrence in a string of a substring, starting at
a specified location, searching forward.
- Required_Reading
SCANNING
- Brief_I/O
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
str I Any character string.
substr I Substring to locate in the character string.
start I Position to begin looking for substr in str.
The function returns the index of the first occurrence of substr in
str at or following index start.
- Detailed_Input
str is any character string.
substr is a substring to look for in str. Spaces in substr are
significant, including trailing blanks.
start is the position in str to begin looking for substr. start
may range from 0 to n-1, where n is the number of
characters in str.
- Detailed_Output
The function returns the index of the beginning of the first
substring of str that begins on or after index start and is equal
to substr. If the substring cannot be found after start, the
function is returns -1.
- Parameters
None.
- Particulars
pos_c is case sensitive.
An entire family of related CSPICE routines
cpos_c
cposr_c
ncpos_c
ncposr_c
pos_c
posr_c
is described in the Required Reading.
- Examples
Let string == "AN ANT AND AN ELEPHANT "
012345678901234567890123456789
Normal (Sequential) Searching:
------------------------------
pos_c ( string, "AN", 0 ) == 0
pos_c ( string, "AN", 2 ) == 3
pos_c ( string, "AN", 5 ) == 7
pos_c ( string, "AN", 9 ) == 11
pos_c ( string, "AN", 13 ) == 19
pos_c ( string, "AN", 21 ) == -1
start out of bounds:
--------------------
pos_c ( string, "AN", -6 ) == 0
pos_c ( string, "AN", -1 ) == 0
pos_c ( string, "AN", 30 ) == -1
pos_c ( string, "AN", 43 ) == -1
Significance of Spaces:
-----------------------
pos_c ( string, "AN", 0 ) == 0
pos_c ( string, " AN", 0 ) == 2
pos_c ( string, " AN ", 0 ) == 10
pos_c ( string, " AN ", 0 ) == -1
- Restrictions
None.
- Exceptions
1) The error SPICE(NULLPOINTER) is signaled if either of
the input string pointers is null.
2) If start is less than 0, the search begins at the first
character of the string.
3) If start is greater than or equal to the length of the string,
pos_c returns -1.
4) The function returns -1 if either of the input strings is empty.
- Files
None.
- Author_and_Institution
N.J. Bachman (JPL)
W.L. Taber (JPL)
- Literature_References
None.
- Version
-CSPICE Version 1.0.0, 15-AUG-2002 (NJB) (WLT)
- Index_Entries
position of substring
- Link to routine source