INSTR Function
 ----------------------------------------------------------------------------


 Action

 Returns the character position of the first occurrence of a string in
 another string.


 Syntax



  INSTR( start%, stringexpression1$,  stringexpression2$)

 Remarks


 The  INSTR function uses the following arguments.

-----------------------------------------------------------------------------
 Argument                                Description
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  start%                                 An optional offset that sets the
                                         position for starting the search;
                                         start% must be between 1 and
                                         32,767, inclusive. If  start% is
 Argument                                Description
 ----------------------------------------------------------------------------
                                         32,767, inclusive. If  start% is
                                         not given, the  INSTR function
                                         begins the search at the first
                                         character of  stringexpression1$.

  stringexpression1$                     The string being searched.

  stringexpression2$                     The string to look for.





 The arguments  stringexpression1$ and  stringexpression2$ can be string
 variables, string expressions, or string literals. The value returned by
 INSTR depends on these conditions.

-----------------------------------------------------------------------------
 Condition                             Value returned
 Condition                             Value returned
 ----------------------------------------------------------------------------
  stringexpression2$ found in          The position at which the match is
 stringexpression1$                    found

  start% greater than length of        0
 stringexpression1$

  stringexpression1$ is a null string  0

  stringexpression2$ cannot be found   0

  stringexpression2$ is a null string   start% (if given); otherwise, 1





 Use the  LEN function to find the length of  stringexpression1$.


 See Also

  LEN


 Example


 The following example uses  INSTR and  UCASE$ to determine a person's gender
 from a courtesy title (Mr., Mrs., or Ms.).

 CLS    ' Clear screen.


 DO


    INPUT "Enter name with courtesy title (Mr., Mrs., or Ms.). ", Nm$


 LOOP UNTIL LEN(Nm$) >= 3





 Nm$ = UCASE$(Nm$) ' Convert lowercase letters to uppercase.


 ' Look for MS, MRS, or MR to set Sex$.


 IF INSTR(Nm$, "MS") > 0 OR INSTR(Nm$, "MRS") > 0 THEN


     Sex$ = "F"


 ELSEIF INSTR(Nm$, "MR") > 0 THEN


     Sex$ = "M"


 ELSE


     ' Can't determine gender, query user.


     DO


         INPUT "Enter sex (M-F). ", Sex$


         Sex$ = UCASE$(Sex$)


     LOOP WHILE Sex$ <> "M" AND Sex$ <> "F"


 END IF


 PRINT "Sex is "; Sex$




 Output

 Enter name. Ms. Elspeth Brandtkeep


 Sex is F





 Enter name. Dr. Richard Science


 Enter sex (M-F). M


 Sex is M