! Title  : TrueBASIC Example 15
! Author : John Walsh
! Date   : 20 May 2000
!
LET first_actual$ = "First"
LET second_actual$ = "Second"
!
PRINT "Values at start of program are :"
PRINT "first_actual$  = "; first_actual$
PRINT "second_actual$  = "; second_actual$
!
CALL exchange (first_actual$, second_actual$)    ! use ((first_actual$), (second_actual$))
! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! to pass parameters by value
!
PRINT "Values at end of program are :"
PRINT "first_actual$  = "; first_actual$
PRINT "second_actual$  = "; second_actual$
END
!
SUB exchange (formal_one$, formal_two$)
    LOCAL swap$
    LET swap$ = formal_one$
    LET formal_one$ = formal_two$
    LET formal_two$ = swap$
END SUB