(1)
IF logical_expression THEN ……… END IF
If logical_expression is true, the part ……… shall be executed.
The part ……… can consist of multiple statements.
Example.
10 ! Solve a quadratic equation. 20 INPUT a, b, c 30 LET D=b^2-4*a*c 40 IF D>=0 THEN 50 PRINT (-b + SQR(D))/(2*a), (-b-SQR(D))/(2*a) 60 END IF 70 END
(2)
IF logical_expression THEN ………1 ELSE ………2 END IF
if logical_expression is true, the part ………1 shall be executed,
otherwise the part ………2 shall be executed.
Example.
10 ! Solve a quadratic equation. 20 INPUT a, b, c 30 LET D=b^2-4*a*c 40 IF D>=0 THEN 50 PRINT (-b + SQR(D))/(2*a), (-b-SQR(D))/(2*a) 60 ELSE 70 PRINT "no solution" 80 END IF 90 END