CS106L(1): Introduction to C++

Core Idea

  • C++: ubiquitous, important, C with classes & many features, safe, efficient
  • how to compile C++ program

Lecture 1 Introduction - Note

View Lecture Note

C++ Philosophy

  • Different C++ codes

    • std::cout, std::endl
    • printf <- a C function
    • asm <- assembly code
  • Assembly

    • pros: simple, fast, complete control
    • cons: lot of code, hard to understand, unportable for different systems
  • C & C++

    • C: no object/classes, no generical functional code, tedious writing large programs
    • C++: C with classes, fast, simple, cross-platform, high-level features, safety, efficiency, abstraction


Compiling Process

Table: 4 Components

Preprocessor Deals with #include, #define, etc directives
Compiler Converts C++ source code into assembly. This process is localised to each .cpp file, output .s files.
Assembler Turns assembled code into object code (.o files). Still no intercommunication between separate cpp files.
Linker Object files are linked together to make an executable program. The first place where files are combined. Check that every declared function has an implementation.

Compiling Ways


Others not listed in lecture notes:

  • Dev C++
  • Microsoft VS
  • Eclipse
  • Xcode

See more at Best C++ IDEs or Source Code Editors for Programming. For some reasons, I gonna use Vim + extensions in this C++ journey.

Command Line Compilation

  • Try Compile C++ Program Compiler: g++ (builtin for Mac, download for Windows)

Basic Usage:

$ g++ main.cpp otherFile.cpp -o execFileName

3 common compiler flags:

-std=c++2a Enable ISO C++ 2020 support
-g Add debugging information to the output
-Wall Turn on most compiler warnings

Typical First C++ Program for beginners

Source Code:

#include <iostream>

int main() {
	std::cout << "Hello World!" << std::endl;


$ g++ hw.cpp -std=c++2a -g -Wall -o hw
$ ./hw


Hello World!

POC: poc

Haha, congrats, first lecture finished!