Homeworks 8 and 9: Vectors, parts 1 and 2

This is a "pair" assignment, which means that if you are working on a team with someone else, you and your partner should do engage in the pair programming model. You should be physically together, sharing a computer and both looking at the same screen. Review the instructions on Moodle about pair programming.

You should make sure that over the course of an assignment that you spend roughly the same amount of time each "driving." My recommendation is to take turns approximately every 10-15 minutes. Set a timer to help you remember. I will also ask you to turn in a form about your partnership when we switch partners and at the end of the term.

If pair programming in real-time just doesn't work for you and your partner, then you will need to amicably split up and work individually. If you choose this option, you must communicate that to me [Anna]. Please do so as soon as that decision is made. If you split, a new partner typically cannot be assigned until the rest of the class switches partners.

Python, Java, and many other languages have the capability for a list implementation that uses an array that automatically expands itself as necessary. In Python it is simply called a "list"; in Java, it is called an "ArrayList". Generically, it is sometimes referred to as a vector or a dynamic array. C has no such built-in vector capability, though it does have fixed-size arrays. For this assignment, you will implement a vector in C. (Note that while C has so-called variable-length arrays, that only means that you can create an array whose size is given by a variable. It’s still the case that once the array is made, it isn’t automatically resized as needed.)

Your assignment is to add to the file vector.c in the same directory as the starter files. You'll eventually be writing code for all the functions prototyped in vector.h. That means you'll have the same functions as in vector.h (as well as any other functions you wish), with the same input and output types. These functions should have bodies (unlike in vector.h). Make sure to read the comments in vector.h carefully so you know what each function should do, and follow all of the instructions in vector.h. You should change only vector.c; please leave the other files untouched - we will be using our versions of these files for testing, so if you make changes, your code may not pass our tests.

Implement the functions init, print, insert, get, and cleanup. For insert, you do not need to make the array automatically double for Part 1. You will need to make sure you have minimal stub code in the remaining functions to make it compile.

As usual, you can test your code for correctness with the test scripts ./test-m and ./test-e. If you want to see the tests themselves, the place to look is in tester.c.

Your code should have no memory leaks or memory errors. We'll test this using valgrind, which is a wonderful tool for detecting memory bugs in C. If valgrind produces error messages, this is considered incorrect, so it's important that you check it yourself. The testing scripts automatically run valgrind on your code, so you'll see those errors as well. Additionally, the test scripts will report failures if you have compilation warnings.

When you run the tests, it's fine if you see a message like FAIL: testVectorPart2. What you don't want is FAIL: testVectorPart1. Part 1 is the tests for part 1, and part 2 is the tests for part 2. For part 1, only the part 1 tests need to pass. (Note that Gradescope will run all the tests. Your part 2 tests will fail, and that's okay. Just look at the details on Gradescope to verify which tests are passing.)

First, let's use the header file a bit more properly now that you've learned more about header files in class. Remove the struct definition and typedef from vector.c, and instead, include the vector.h header file; remember that for includes that aren't part of the standard C library, you'll use quotation marks rather than angle brackets. Test your code using test-m and test-e: the results of the tests should not have changed from before removing the struct definition. If they have, double check what you've done, and make sure you didn't change anything about the struct definition: the version in vector.c should have been identical to the version in vector.h. py Implement any remaining functions that you skipped in Part 1 that were in vector.h, and modify your insert to make the array automatically double in size when needed (as described in the comment for insert).