IF ~ END IF ☆☆☆

(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