This is mostly a reminder/refresher on C. It also makes use of the introduction to makefiles.

1 Three files

Write the following files:

main.c

contains a main function. If there are command-line arguments, convert each to an integer and invoke pprime with each. If there are no command line arguments, read integers from standard input (provided in base-10, one number per line) until the end of standard input is reached and invoke pprime with each integer. main should not print anything itself.

primes.c

contains (at least) three functions:

isprime

Accepts a single integer and returns 1 if it is prime, 0 otherwise. You are welcome to brute-force this or use the primality checking from COA1’s smallc program.

nextprime

See COA1’s smallc for a description.

pprime

Given an integer, print a single line to standard out containing either

(number) is prime

or

(number) is not prime, but (bigger number) is

where (number) is the argument integer and (bigger number) is the result of invoking nextprime on the argument

Do not include the parentheses in your actual output; correct formatting is

3 is prime
4 is not prime, but 5 is

primes.h

contains the header for pprime, isprime, and nextprime.

Also create a makefile named Makefile such that typing

make

will rebuild (if necessary) primes.o and main.o and link them together into an executable primes.

See info make for detailed converation about how make works; https://www.gnu.org/software/make/manual/make.html for online documentation; and https://www.gnu.org/software/make/manual/make.html#Rule-Example for an example to work from.

If your code uses any function in math.h (such as sqrt, pow, log, etc.), make sure you add -lm to the LDFLAGS of your Makefile or it will not compile on the department servers.

2 Collaboration

This assignment is intended to be exploratory and get your feet wet; you are welcome to help one another with it as much as you wish. However, you are responsible for both (a) citing help and (b) understanding what you submit.