Welcome to CS 106L!
Ali Malik
malikali@stanford.edu
Game Plan
Welcome
Why CS106L?
Logistics
History and Philosophy of C++
C++ Basics
Welcome!
Instructor
Ali Malik
malikali@stanford.edu
Instructor
Ali Malik
malikali@stanford.edu
Email me whenever you have questions or even if you just
want to talk. I’d love to hear from all of you!
Tell me about the things you are working on, or anything you
find interesting.
You
You
Civil and
MCS Petroleum Eng. Environmental Eng.
Undeclared MS&E Biology Statistics
Symbolic Systems Physics Music Aero/Astro
Computer Science Mathematics Education
Economics Energy Resource Eng. Material Science
Electrical Eng. MBA Mechanical Eng.
Why CS106L?
What is CS106L?
CS106B/X:
● Focus is on teaching concepts like abstractions, recursion,
pointers etc.
● Only teaches you enough C++ to practice these concepts.
CS106L:
● Learn how to write powerful and elegant code.
● Write actual C++ - no Stanford libraries!
● Understand the design decisions that lead to “good” code
Good C++ Code
#include <iostream>
int main() {
std::cout << "Hello, world!" << std::endl;
return 0;
}
“Good” C++ Code
#include "stdio.h"
#include "stdlib.h"
int main(int argc, char *argv) {
printf("%s", "Hello, world!\n");
return EXIT_SUCCESS;
}
“Good” C++ Code
#include "stdio.h"
#include "stdlib.h"
int main(int argc, char *argv) {
asm( "sub $0x20,%rsp\n\t"
"movabs $0x77202c6f6c6c6548,%rax\n\t"
"mov %rax,(%rsp)\n\t"
"movl $0x646c726f, 0x8(%rsp)\n\t"
"movw $0x21, 0xc(%rsp)\n\t"
"movb $0x0,0xd(%rsp)\n\t"
"leaq (%rsp),%rax\n\t"
"mov %rax,%rdi\n\t"
"call __Z6myputsPc\n\t"
"add $0x20, %rsp\n\t"
);
return EXIT_SUCCESS;
}
“Good” Terrible C++ Code
#include "stdio.h"
#include "stdlib.h"
int main(int argc, char *argv) {
asm( "sub $0x20,%rsp\n\t"
"movabs $0x77202c6f6c6c6548,%rax\n\t"
"mov %rax,(%rsp)\n\t"
"movl $0x646c726f, 0x8(%rsp)\n\t"
"movw $0x21, 0xc(%rsp)\n\t"
"movb $0x0,0xd(%rsp)\n\t"
"leaq (%rsp),%rax\n\t"
"mov %rax,%rdi\n\t"
"call __Z6myputsPc\n\t"
"add $0x20, %rsp\n\t"
);
return EXIT_SUCCESS;
}
Why Learn C++?
Why C++: Popularity
TIOBE Index, March 2017
Why C++: Popularity
Most loved languages - StackOverflow 2015
Why C++: Users (companies)
Why C++: Users (browsers)
Why C++: Users (software)
Why C++: Users (games)
Why C++: Users (cool things)
The Spirit rover was operational for
over 6 years when the mission was only
planned to run for around 3 months
The F-35 Lightning II (Joint Strike Fighter)
relies extensively on C++
Logistics
Logistics
Lecture T/Th 1:30 - 2:20pm in Shriram 104.
Website cs106l.stanford.edu
Office Hours TBA. Email if any help needed till then.
Assignments 3 in total - you need to do at least 2 to pass.
Late Days Three 24-hr late days (max two per assignment).
Development We will be using QT Creator. Get this set up quickly!
Honor Code Don’t cheat, repercussions are severe.
Logistics
Lecture T/Th 1:30 - 2:20pm in 200-030. QT Help hours
this Thursday
Website cs106l.stanford.edu
Office Hours TBA. Email if any help needed till then.
Assignments 3 in total - you need to do at least 2 to pass.
Late Days Three 24-hr late days (max two per assignment).
Development We will be using QT Creator. Get this set up quickly!
Honor Code Don’t cheat, repercussions are severe.
What is C++?
C++ History
“If you wish to make an apple pie from
scratch, you must first invent the
universe”
- Carl Sagan
C++ History
“If you wish to understand C++ from
scratch, you must first invent the
universe”
- (not) Carl Sagan
C++ History: Assembly
section .text
global _start ;must be declared for linker (ld)
_start: ;tell linker entry point
mov edx,len ;message length
mov ecx,msg ;message to write
mov ebx,1 ;file descriptor (stdout)
mov eax,4 ;system call number (sys_write)
int 0x80 ;call kernel
mov eax,1 ;system call number (sys_exit)
int 0x80 ;call kernel
section .data
msg db 'Hello, world!',0xa ;our dear string
len equ $ - msg ;length of our dear string
C++ History: Assembly
Unbelievably simple instructions (move bits around, add, subtract).
Well written assembly is extremely fast.
Gives you complete control over your program.
Why don’t we always use assembly?
C++ History: Assembly
section .text
global _start ;must be declared for linker (ld)
_start: ;tell linker entry point
mov edx,len ;message length
mov ecx,msg ;message to write
mov ebx,1 ;file descriptor (stdout)
mov eax,4 ;system call number (sys_write)
int 0x80 ;call kernel
mov eax,1 ;system call number (sys_exit)
int 0x80 ;call kernel
section .data
msg db 'Hello, world!',0xa ;our dear string
len equ $ - msg ;length of our dear string
C++ History: Assembly
Requires lots of code to do simple tasks.
Hard to understand other people’s code
Extremely unportable
C++ History: Moving Forward
Writing assembly was too difficult but computers only understood
assembly.
Idea:
● Source code can be written in a more intuitive language
● An additional program can convert it into assembly
This is called a compiler!
C++ History: Invention of C
K&R created C in 1972, to much praise.
C made it easy to write code that was
● Fast
● Simple
● Cross-platform
Ken Thompson and Dennis Ritchie,
creators of the C language.
Learn to love it in CS107!
C++ History: Invention of C
C was popular since it was simple.
This was also its weakness:
● No objects or classes (think cmap/cvec)
● Difficult to write code that worked generically
● Tedious when writing large programs
C++ History: Bjarne Stroustrup
In 1983, the first vestiges of C++ were created by Bjarne
Stroustrup.
He wanted a language that was:
● Fast
● Simple to Use
● Cross-platform
● Had high level features
C++ History: Bjarne Stroustrup
In 1983, the first vestiges of C++ were created by Bjarne
Stroustrup.
He wanted a language that was:
● Fast
● Simple to Use
● Cross-platform
● Had high level features
C++ History: Bjarne Stroustrup
In 1983, the first vestiges of C++ were created by Bjarne
Stroustrup.
He wanted a language that was:
● Fast
● Simple to Use
● Cross-platform
● Had high level features
C++ History: Evolution of C++
C++ C++03 C++14
1979 1983 1998 2003 2011 2014 ?
C with
C++98 C++11 C++17
Classes
C++ History: Evolution of C++
C++ C++03 C++14
1979 1983 1998 2003 2011 2014 ?
C with
C++98 C++11 C++17
Classes
You are here
The C++ Philosophy
Only add features if they solve an actual problem
Programmers should be free to choose their own style
Compartmentalization is key
Allow the programmer full control if they want it
Don’t sacrifice performance except as a last resort
Enforce safety at compile time whenever possible
The C++ Philosophy
Only add features if they solve an actual problem
Programmers should be free to choose their own style
Compartmentalization is key
Allow the programmer full control if they want it
Don’t sacrifice performance except as a last resort
Enforce safety at compile time whenever possible
The C++ Philosophy
Only add features if they solve an actual problem
Programmers should be free to choose their own style
Compartmentalization is key
Allow the programmer full control if they want it
Don’t sacrifice performance except as a last resort
Enforce safety at compile time whenever possible
The C++ Philosophy
Only add features if they solve an actual problem
Programmers should be free to choose their own style
Compartmentalization is key
Allow the programmer full control if they want it
Don’t sacrifice performance except as a last resort
Enforce safety at compile time whenever possible
Our first C++ Program
hello.cpp
#include <iostream>
int main() {
std::cout << "Hello, world!" << std::endl;
return 0;
}
Next Time
Streams
