Интерполяция по формуле лагранжа

DECLARE FUNCTION LX! (k AS INTEGER, x() AS SINGLE, y() AS SINGLE, xL AS SINGLE)
DIM xL AS SINGLE, x AS SINGLE, y AS SINGLE, E AS SINGLE, E1 AS SINGLE, A AS SINGLE, L(k) AS SINGLE
DIM n AS INTEGER
 
CLS
INPUT "znachenie argumenta dlya vichisleniya L(xl):"; xL
INPUT "tochnost interpolyacii:"; E
INPUT "chislo uzlov interolyacii = n+1, n=:"; nO
 
FOR i = 0 TO n
PRINT "x("; i; ")=";
INPUT x(i)
PRINT "y("; i; ")=";
INPUT y(i)
NEXT i
 
k = 1
L = LX(k, x(), y(), xL)
L(k) = L
 
DO
        A = L
        k = k + 1
        L = LX(k, x(), y(), xL)
        L(k) = L
        E1 = ABS(L - A)
LOOP UNTIL (E1 < E) OR (k >= n)
 
FOR i = 1 TO k
PRINT "L("; k; ")="; L(k); SPC(5);
NEXT i
 
FUNCTION LX (k AS INTEGER, x() AS SINGLE, y() AS SINGLE, xL AS SINGLE)
L = 0
FOR i = o TO k
l1 = 1
  FOR j = 0 TO k
    IF i <> j THEN
    l1 = ((xL - x(i)) / (x(i) - x(j))) * l1
    ELSE
    END IF
  NEXT j
L = L + l1 * y(i)
NEXT i
LX = L
END FUNCTION