CMSC313, Computer Organization & Assembly Language Programming, Fall 2012

Project 5: Polynomials

Due: Thursday October 18, 2012, 11:59pm

Objective

Assignment

You must implement the functions add_poly, sub_poly, mul_poly and print_poly. These implementations should go in a separate .c file.

Once you have implemented these functions, then you can use polynomials in the main function simply by calling functions like this:

Implementation Notes

• Please actually read these implementation notes. A lot of questions are from students who haven't read the notes. If you have questions about something in the notes, then by all means ask and we are happy to answer them. But, please actually read these notes.

• You must work with the header file poly5.h given in /afs/umbc.edu/users/c/h/chang/pub/cs313/poly5.h You are not allowed to alter this file.

• The deg field is the highest degree of the polynomial. The coefficients of the polynomial are stored in the coeff array. For example, the polynomial -2 x³ + x² - x + 2 is represented in a variable p by: poly p ; p.deg = 3 ; p.coeff[0] = 2 ; p.coeff[1] = -1 ; p.coeff[2] = 1 ; p.coeff[3] = -2 ; Make sure you are not off by one. Also note that the smallest degree comes first.

• The constant MAX_DEG has the highest degree polynomial that your program has to handle. The degree of a polynomial is the largest exponent. In the example, above -2 x³ + x² - x + 2 has degree 3.

• Do NOT assume that uninitialized parts of the coeff[] array are 0. In the example above, p.coeff[4], p.coeff[5], p.coeff[6], ... , p.coeff[MAX_DEG] may hold garbage values.

• Yes, you are passing struct parameters by value and returning a struct value from your functions. This is usually frowned upon and declared to be "inefficient" (which it may well be). Nevertheless, passing and returning a struct by value is allowed by C.

• If you don't remember how to multiply polynomials, please review. For example:

  (−2 x³ + x² − x + 2) (3 x + 1) = −6 x⁴ + x³ − 2 x² + 5 x + 2

• A small test file is available at: /afs/umbc.edu/users/c/h/chang/pub/cs313/main5.c The output of the main5.c program, when compiled with your implementation of the poly functions, should look something like: -2 x^3 + x^2 - x + 2 plus 3 x + 1 equals -2 x^3 + x^2 + 2 x + 3 -2 x^3 + x^2 - x + 2 minus 3 x + 1 equals -2 x^3 + x^2 - 4 x + 1 -2 x^3 + x^2 - x + 2 times 3 x + 1 equals -6 x^4 + x^3 - 2 x^2 + 5 x + 2

• You must also make your own test cases and submit them.

• Your program should report an error in mul_poly() if multiplying the two polynomials would result in a polynomial with a degree that exceeds MAX_DEG. In this case, you can return anything to the main program.

Extra Credit

• It should make a special case for the leading term.
• It should make a special case for the linear and constant terms.
• It should avoid printing a term when the coefficient is zero.
• It should avoid printing a coefficient when the coefficient is 1.
• It should subtract instead of adding a negative term.

Turning in your program

Use the UNIX submit command on the GL system to turn in your project.

When you are done, use the script Unix command to record yourself running your program.

You should submit 3 files: main5.c, poly5.c and typescript. You should not submit poly5.h since this must be identical to the one distributed. Note: main5.c must have test cases that demonstrate the features of your program. You should not rely on the simple test cases in the original main5.c.

The UNIX command to submit should look something like:

submit cs313 proj5 main5.c poly5.c typescript