REM Euler Pseudoprime Test
REM Robert Campbell, 970701
DECLARE FUNCTION gcd& (x&, y&)
DECLARE FUNCTION powmod& (number&, exponent&, modulus&)

PRINT "Test number for primality using Euler test"
INPUT "number = "; thenumb&
PRINT powmod&(2, thenumb& - 1, thenumb&), powmod&(3, thenumb& - 1, thenumb&), powmod&(5, thenumb& - 1, thenumb&)
IF ((powmod&(2, thenumb& - 1, thenumb&) = 1) AND (powmod&(3, thenumb& - 1, thenumb&) = 1) AND (powmod&(5, thenumb& - 1, thenumb&) = 1)) THEN
        PRINT "Prime (probably, testing w/ bases 2, 3 and 5)"
ELSE
        PRINT "Composite"
END IF
END

FUNCTION powmod& (number&, exponent&, modulus&)
e& = exponent&
accum& = 1
pow2& = number&
WHILE (e& > 0)
        IF ((e& MOD 2) = 1) THEN accum& = (accum& * pow2&) MOD modulus&
        pow2& = (pow2& * pow2&) MOD modulus&
        e& = e& \ 2
WEND
powmod& = accum&
EXIT FUNCTION
END FUNCTION