CSE 333 25su Exercise 5

out: Wednesday, July 02, 2025
due: Monday, July 07, 2025 10:00 am. No late exercises accepted.

Goals: Continue exploring multi-file C programs by adding details not part of the previous exercise: header guards, internal linkage for "private" helper functions

Description: In this exercise we will modify the implementation of the multi-file C program from the previous exercise. The specification remains exactly the same. The program should have the following three files (specification copied with no changes from the previous exercise, except that ex4.c should be renamed ex5.c):

• NthPrime.h: a header file, containing a single function prototype declaration for a function called NthPrime(), as well as comments above the prototype documenting how to use the function. The function should accept a single int16_t parameter, and it should return an int64_t. The function should return the nth prime number, where n is the function's parameter. Note that NthPrime(1) should return 2, NthPrime(2) should return 3, NthPrime(3) should return 5, and so on. The result of NthPrime(n) is not defined if n <= 0, and implementations do not need to check for this possibility.
  
• NthPrime.c: a file containing the implementation of NthPrime. Feel free to use the simplest possible primality testing algorithm (hint: "x is not prime if it is divisible by ..."). You may also want to define some helper functions here as well.
  
• ex5.c: a file containing a main() function that tests NthPrime by printing the input and output output of NthPrime for at least two different, non-trivial arguments (but you do not need to print an enormous number of test cases - keep it reasonable).

Your implementation must:

• Include proper header guards in the NthPrime.h header file,
• Use static to ensure that "private" helper functions (if any) in NthPrime.c have internal, not external linkage and thus are not visible to other files, and

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Your code must:

• compile without errors or warnings on CSE Linux machines (lab workstations, attu, or CSE home VM)
• have no crashes, memory leaks, or memory errors on CSE linux machines
• be contained in the three files described above. We will compile your code with the following commands (and you should too):

  
  bash$ gcc -Wall -g -std=c17 -c -o NthPrime.o NthPrime.c
  
  bash$ gcc -Wall -g -std=c17 -c -o ex5.o ex5.c
  
  bash$ gcc -Wall -g -std=c17 -o ex5 ex5.o NthPrime.o

• be pretty: the formatting, modularization, variable and function names, and so on must make us smile rather than cry. (Suggestion: see if cpplint --clint reports any problems. However, you may ignore warnings from cpplint --clint about the header guard #define name not including a full file path as long the identifier has an otherwise appropriate name.)
• be robust: you should think about handling bogus input from the user, and you should handle hard-to-handle cases (if there are any) gracefully.
• have a comment at the top of each of your files with your name, student number, and CSE or UW email address.

You must not submit any generated or editor files, just the .c and .h files.

You should submit your exercise using the Gradescope dropbox linked on the course resources web page.