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INSTR Function Programming Example
 
This example uses INSTR and UCASE$ to determine a person's sex from
their courtesy title (Mr., Mrs., or Ms.).
 
' Get a name.
CLS    ' Clear screen
DO
   INPUT "Enter name including courtesy title (Mr., Mrs., or Ms.): ", Nm$
LOOP UNTIL LEN(Nm$) >= 3
 
' Convert lowercase letters to uppercase.
Nm$ = UCASE$(Nm$)
' 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 sex, query user.
    DO
        INPUT "Enter sex (M/F): ", Sex$
        Sex$ = UCASE$(Sex$)
    LOOP WHILE Sex$ <> "M" AND Sex$ <> "F"
END IF
' Print result
PRINT "Sex is "; Sex$
 
Sample Output
 
Enter name: Ms. Elspeth Brandtkeep
Sex is F
 
Enter name: Dr. Richard Science
Enter sex (M/F): M
Sex is M