lect01, Tue 04/02

Introductions and Course overview

Course Logistics

• If you have not yet, familiarize yourself with the syllabus.
• Due to the large amount of emails, it may take a while for Prof. K to respond
  • Because of this, please add “CS 16” to the title of every email
  • Use this address for a faster response: ykk-class+cs16s19 @cs.ucsb.edu (remove the space before @)
• For 1-on-1 help, tutors and TAs are available during closed and open lab hours (open lab hours will begin during week 2)

Parts of a Computer

A computer can be divided into two major parts, hardware and software

• Hardware are the physical parts of the computer, like the CPU, RAM, etc.
• Software are the data instructions that runs on the hardware, like the operating system and programs

In an abstract view, a computer can be divided into 5 hardware components

1. Input devices
   • keyboard, mouse, microphone, touchscreen, anything that’s used to input data to the computer
2. Output devices
   • monitor, speakers, anything that the computer outputs data to
3. Processor
   • The Central Processing Unit (CPU). This is the brain of the computer, and it’s where calculations are getting done.
4. Main memory
   • The RAM (random-access memory), ROM (read-only memory), etc.
   • The main memory is volatile, meaning that data is lost when the computer powers down.
5. Secondary memory
   • This is your storage, like hard drives/SSDs, but can also be in the form of a USB drive or a floppy disk (anyone remembers those?)
   • Secondary memory is significantly slower, but is non-volatile: the data is saved even when the computer is off

This method to divide a computer into theses 5 parts is known as the von Neumann architecture.

Basic Structure of a C++ Program

C++ file containing C++ code has the filename extension .cpp

A basic C++ program usually looks like the following:

#include <iostream> //This adds the basic input/output functions

using namespace std;  //a directive for using standard functions

int main()
{
  //Write your code here
  
  
  return 0; // ends the program, and indicates the program has finished successfully
}

In your program, you want to return a non-zero number to indicate that a program terminated abnormally.

The C++ Compilation Process

Compared to Python, where you write and then run the code under IDLE, C++ programs must be compiled.

During the compilation process, a compiler turns the program you write into something a computer understands (binary code).

Therefore, you end up with 3 parts of creating a program in C++:

1. Editing: writing the code in a text file
2. Compiling: translating the code to something a computer can understand (a binary version of the code)
3. Running: executing the binary version of the code on the computer

Later in the course we will learn more tricks to save time compiling. For a small program, re-compiling may take a small amount of time, but for large programs, anything we can optimize will speed up the compile time, e.g., only re-compiling the files we changed.

Practice Questions

1. What is firmware?