CS 3520 Homework 7   - Due October 18

Exercise 7.1, Set! finger exercises

• Complete the following Scheme definition (replace the "..."):

            (define (ex1 v1 v2)
             (let ([f ...])
               (f v1)
               (f v2)))

  so that the value of (ex1 n m) is n+m for any integers n and m. The catch is that neither v1 nor v2 may appear in anywhere within the expression replacing "...".

• Complete the following Scheme definition (replace the "..."):

            (define (ex2 v1 v2)
             (let ([mk ...])
               (let ([f (mk)]
                     [g (mk)])
                 (f v1)
                 (g v2)
                 (g 0))))

  so that the value of (ex2 n m) is n+m for any integers n and m. As before, neither v1 nor v2 may appear in anywhere within the expression replacing "...".

• Complete the following Scheme definition (replace the "..."):

            (define (ex3 v1 v2)
             (let ([mk ...])
               (let ([f (mk)]
                     [g (mk)])
                 (f v1)
                 (g v2)
                 (g 0))))

  so that the value of (ex3 n m) is m for any integers n and m. As always, neither v1 nor v2 may appear in anywhere within the expression replacing "...".

• Complete the following Scheme definition (replace the "..."):

            (define (ex4 v1 v2 v3 v4)
             (let ([mk ...])
               (let ([f (mk)]
                     [g (mk)])
                  (f v1 v2)
                  (g v3 v4)
                  (list (f 0 0) (g 0 0)))))

  so that the value of (ex4 n m p q) is _(n+m+q m+p+q)_ for any integers n, m, p, and q. Of course, v1, v2, v3, or v4 may not appear in anywhere within the expression replacing "...".