IF a#$ = < <= > >= <> b#$
| ELSEIF ...
IF a#$ = < <= > >= <> b#$ THEN ...
An ELSEIF statement indicates a new condition to be evaluated in the instance that the initial condition evaluates to a false state. It also marks the beginning of a code block to be executed in the event that this new condition evaluates to a true state.
PRINT "a>5", 0,0
PRINT "a<=5, but b>5", 0,0
PRINT "Neither a nor b > 5", 0,0
You can use the command THEN if you only want one command to be executed if the comparison is TRUE.
IF a < b
PRINT "a < b", 100, 100
PRINT "a < b is FALSE", 100, 100
IF a<>b THEN PRINT "a is not b", 100, 150
a < b is FALSE
a is not b