# 程序代写代做代考 scheme data structure CSc 600: PROGRAMMING LANGUAGE DESIGN

CSc 600: PROGRAMMING LANGUAGE DESIGN

CSc 600: PROGRAMMING LANGUAGE DESIGN Dr. Jozo Dujmović

Scheme

1. The concept of first class objects is fundamental for Scheme programming. In particular, in

Scheme functions are first class objects. The main properties of functions as first class objects
are exemplified by answering the following questions:
(a) The first class object may be expressed as an anonymous literal value (constant). Show

an example of the anonymous function and its use.
(b) The first class object may be stored in variables (i.e. it may have a symbolic name).

Show examples of defining and using named functions.
(c) The first class object may be stored in data structures. Show an example of a data

structure(e.g. a list) that contains functions
(d) The first class object may be comparable to other objects for equality. Show an

example of comparing functions and lists for equality.
(e) The first class object may be passed as parameter to procedures/functions. Show an

example of passing function as an argument to another function.
(f) The first class object may be returned as result from procedures/functions. Show an

example of returning a function as a result of another function.
(g) The first class object may be readable and printable. Show examples of reading

function(s) from the keyboard, reading function(s) from a file, and displaying a
function.

2. [This problem was used for the final exam]

The mean value of n numbers is nxxx n /)…( 1 ++= . The mean value of n squares is

nxxx n /)…(
22

1
2 ++= . The standard deviation is defined as 22 )(σ xx −= . Write a Scheme

function sigma that computes the standard deviation of any number of arguments, as in the
following example:

[55] (sigma 1 2 3 2 1)
0.748331477354788
[56] (sigma 1 3 1 3 1 3)
1.
[57] (sigma 1 3)
1.
[58] (sigma 1)
0.

3. [This problem was used for the final exam]

(a) Write a recursive Scheme procedure line that prints n asterisks in a line as follows:

(line 5)

1
*****

2

(b) Write a recursive Scheme procedure histogram that uses the procedure line, and prints a
histogram for a list of integers:

(histogram ’(1 2 3 3 2 1))
*
**
***
***
**
*

4. Write a Scheme program for computing a maximum of function f(x) within the interval [x1,
x2]. Use the trisection method, and find the coordinate of maximum xmax with accuracy of 6
significant decimal digits.

5. Develop a program that computes the scalar product of two vectors. The program must not
accept vectors having different size (in such a case print an error message). For example:

>(scalar-product ‘#(1 2 3) ‘#(2 1 1))
7
>(scalar-product ‘#(1 2 3) ‘#(1 2 3 4 5))
ERROR: Different sizes of vectors!
>

(a) Write the program in iterative style using the DO loop.

(b) Write the program using recursion.

6. The files “matrix1.dat” and “matrix2.dat” are created using a text editor and contain two
rectangular matrices. For example,

matrix1.dat: matrix2.dat:

2 3 3 3
1 2 3 1 2 3
4 5 6 1 2 3
1 2 3

In both cases the first row contains the size of the matrix (the number of rows and the number of
columns). The remaining rows contain the values of elements.

(a) Develop programs row and col that read a matrix from a file and display a specified row

3

or column. For example:

> (row “matrix1.dat” 2)
4 5 6
> (col “matrix1.dat” 2)
2 5

Matrices should be stored in memory as vectors whose components are vectors.

(b) Develop a program for matrix multiplication mmul that multiplies two matrices stored
in specified input files, and creates and displays an output file containing the product. For
example:

> (mmul “matrix1.dat” “matrix2.dat” “matrix3.dat”)
6 12 18
15 30 45

In this example the contents of the new file “matrix3.dat” should be

2 3
6 12 18
15 30 45

_______________________________________________________________________________

NOTES: All Scheme programs must be presented as complete transcripts which include the
headers with author name, program name, program description, date, and homework and problem
numbers (e.g. HW1/4). Transcripts must include sample program outputs. All critical points in a
program must be explained using comments. Late homework cannot be accepted.

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