CS208 Introduction to Computer Systems
Wednesday, 17 September 2025

+ Today
- Integers
- More class logistics
- More integers

+ Writing integers
- Decimal       197
- Binary        0b11000101
- Octal         0305
- Hexadecimal   0xC5

    What I want:
    - You can convert binary to decimal
    - You can convert hexadecimal to decimal
    - **You can convert binary to hexadecimal and back
    - (If you want to get good at decimal to binary, go nuts,
        but no big deal)

- Try 0b10101101 -> decimal
- Try 0b10101101 -> hexadecimal
    1010 1101 --> 0xAD --> 10x16 + 13x1 = 173

- initializing and printing in C

+ Plans for this class
- Grading summary
    - Assignments
    - Labs
    - Quizzes (paper)
    - Exams
- Assessments in person and on paper
- Week 4: In-class exam (C and data representation)
- Week 9: In-class exam (assembly language, etc.)

+ LLMs in CS classes
- how have you been using them?
- do they help you learn?
- suggestions on how profs should respond?
- ...

+ Integers and ints
- int, 32 bits, 4 bytes
- Bitwise operators in C (bitwise.c)

+ Negative integers in int variables
- how to store a negative integer value in an int?
- two's complement