Still under construction. Any question, please send email to me (tunan@paul.rutgers.edu).

1. Since the {} is equivalent to *, this language is all the strings which begin

with a digit except 0 and end with a digit except 0, and have exactly one '.' in the middle.

2.

NFSA

DFSA

3.

D = &&B will incur an error, since we can’t do referencing two times on any variable.

A = ***C will not incur an error, since do dereferencing three times on a variable with int *** is valid.

4.

int main()

{

int a = 7;

int *ra;

int **x;

int ***b;

int ****y, ****z;

ra = &a;

x = &ra;

b = &x;

y = z = &b;

return 0;

}

Scheme:

1. (define (size? L p) (if (eq? (length L) p) #t #f))

2. to see if there is a duplicate member in L.

3.

(define (rp? L)

(if (null? L) #f

(let (rest (cdr L))

(if (member? (car L) rest) #t

(rp? rest)

)

)))

4.

(define (add1 x)

(+ x 1))

(define (incr L)

(cond (( null? L) '())

(else (cons (add1 (car L))

(incr (cdr L))) )

))

5

(define (incr L)

(map add1 L))

6.

g = 0 if argument is 0

= 1 if argument is positive

= -1 if argument is negative

(define (g x) (cond ((> x 0) 1)

((= x 0) 0)

(else -1)

))

(define (ff L) (map g L))

Grammar:

(1) 1000 is in the language.

(2) the small shortest string is 10.

G

|

S

/ \

1 X

|

0

(3) one 1 follow by at least one 0.

(4) 10+

(5)

(6)

false

true

true

? ( I am not sure what sentential ..is)

false

true

(7)

(a) impossible, since the value of the y and z is address of other

variable which is not changable.

(b)

x = 5;

printf("%d \n", x);

x = 10;

printf("%d \n", x);

printf("%d \n", x);

(c)(d) I couldn't see any output indicated.