CS208 Introduction to Computer Systems
Wednesday, 21 January 2026

+ Friday and the ICE Out of MN walkout
- no new material, but I'll hang out here
- I'll provide exercises to practice on
    (and post them for people who choose not to come)
- I'm happy to talk about what's going on, if you want to

+ The tar thing
- why tar at all?
- polite tarring: put everything in a folder
- source of confusion
- no penalty for assignments so far if you resubmit by tonight

+ Questions

+ High-level pointer/memory topics
- memory layout; where is everything?
- relevant C syntax
- uses of addresses

+ Try drawing a picture to explain what happens here.

    int something(char *s) {
        assert(s != NULL);

        int k = 0;
        char *p = s;     // <---- IMPORTANT! THIS COPIES THE ADDRESS!
        while (*p != '\0') {
            k++;
            p++;
        }

        return k;
    }

    int main() {
        char a[10] = "goat";
        int n = something(a);
        printf("%d\n", n);
        return 0;
    }

+ Memory layout for any running program
- OS
- Program Code
- Global read-only memory: string literals, etc.
- Heap
- Stack