RosettaCodeData/Task/Modular-inverse/True-BASIC/modular-inverse.basic

SUB modularinverse(e,t)
    LET d = 0
    IF e < t then
       LET b = e
       LET c = 1
       DO WHILE b > 1
          LET s = int(((t-b)/e)+1)
          LET b = b+s*e
          LET c = c+s
          LET b = b-t
       LOOP
       LET d = c
    END IF
    LET m = d
    PRINT m
END SUB

CALL modularinverse(42,2017)
CALL modularinverse(40,1)
END