1. Created by Hwansoo Han Edited by Ikjun Yeom
C++ (intro)
Created by Hwansoo Han
Edited by Ikjun Yeom

2. Why New Languages? Already know C++ C, Java, Python, Matlab, …
Basically extension to C
All C code compiled with C++ compilers
But many libraries and “OO” concepts added

3. Many Use C++ Most recent open source projects Natural extension to C
Written in C++ or Java
Easier to understand – “OO” design
Natural extension to C
C and C++ can be easily mixed (with a little efforts)

4. Hello, World! /* * First program in C++ : hello world */
#include <iostream>
using namespace std;
// main function
int main() {
cout << “hello, world!” << endl;
return 0; }
console output
Comment, header include, main, cout

5. C++ IDE Download Cygwin Download JRE 6.0 or above
Set PATH to include g++ or gcc
(제어판>시스템및보안>시스템>고급시스템설정>고급tab>환경변수)
Download JRE 6.0 or above
Google “JRE 64bit windows 7”
E.g. Downloads.cnet.com
Run the downloaded file to install JRE
Download Eclipse CDT (C/C++ development tooling)
Download “Eclipse IDE for C/C++ Developers”
Unzip the downloaded file into a directory
E.g. D:\bin\

6. Genealogy of Programming Languages

7. C++ vs. C vs. Java: Minor Differences
Boolean type
C: int myBooleanValue = 1;
C++: bool myBooleanValue = true;
Java: boolean myBooleanValue = true;
Printing
C: printf(“Hello!\n”);
C++: cout << “Hello!” << endl;
Java: println(“Hello!”);

8. C++ vs. C vs. Java: Minor Differences
Calling other functions
C/C++ : define before use
Java : no such worries
void PrintHello();
void PrintTime() { cout << “It’s time to go!” << endl; }
int main() {
PrintHello(); // OK – Prototype defined earlier
PrintTime(); // OK – Function defined earlier
SayHi(); // ERROR – no prototype earlier }
void PrintHello() { cout << “Hello!” << endl; }
void SayHi() { cout << “Hi!” << endl; }

9. C++ vs. C vs. Java: Major Differences
C/C++ has no garbage collector
Java: Integer myInt = new Integer();
myInt = NULL; // GC will delete
C++ : programmers need to delete
C : programmers need to free
Objects
Java : memory for all objects is put on the heap
C++ : Objects can be placed either on the stack or the heap
C : no objects, malloc gets the space from the heap

10. Program Images, Variables, Objects
Address space
Local variables : stack
Global variables : data
Dynamically allocated objects : heap
code
data
heap
stack
kernel
0xC
0xFFFFFFFF
0x080482d0
int a = 1; // ?
int main() {
int b = 1; // ?
int *c; // ?
c = (int*)malloc(sizeof(int)); // ? }
a: data, b,c: stack, *c(malloc): heap

11. C++ vs. C vs. Java: Major Differences
Stack vs. Heap allocation in C/C++
int main() {
int a = 1; // STACK
int b(2); // STACK
int *c = new int(3); // HEAP
cout << “a=“ << a << “ addr=“ << &a << endl;
cout << “b=“ << b << “ addr=“ << &b << endl;
cout << “c=“ << *c << “ addr=“ << c << endl;
delete c; }
int fn() {
int *parray = new int [10]; // STACK
// …
delete [] parray;
a: stack, b: stack, c: heap

12. C++ vs. C vs. Java: Major Differences
C++ can choose to pass by value, pointer, and reference
C can choose to pass by value or pointer
Java cannot choose
Primitives only pass by value
Objects only pass by reference
/* C */
void AddOne(int *x) { (*x)++; }
int main() {
int x = 7;
AddOne(&x);
printf(“%d\n”, x); // output 8 }
/* C++ */
void AddOne(int &x) { x++; }
int main() {
int x = 7;
AddOne(x);
cout << x << endl; // output 8 }
/* Java */
void AddOne(int x) { x++; }
void run() {
int x = 7;
AddOne(x);
println(x); // output 7 }

13. Coding Style – Managing Large Code
Instead putting all into a single file, separate them for easier management
Files with extension .cpp/.cc contains implementations of functions
Files with extension .h contains function prototype
.h files are used to overall shape of source code
Other programmers can roughly recognize your programs through header files (.h files)
If you don’t care the details on how a function works, you don’t have to look into .cpp files.

14. C++ vs. C vs. Java: Similarities
Short circuit evaluation
if (x < 4 || y == 3) // test the first (x<4), if true skip the second
Integer division
9/4 ⇒ 2
Primitives
char, short, int, long, float, double
Type conversion
3/2.0 ⇒ 1.5
⇒ 18.2
Functions, objects (C++/Java), arithmetic operators, …

15. First Assignment – Guess Number
Print out “Welcome to guess game!”
Declare a variable secret (0..100)
Print out the range of secret value
Set secret value with random()
Loop until exit
Get a guess from the user
If the guess is equal to secret, exit
Print if the guess is high or low
Print out “Congratulations!”
/* C++ random value */
#include <cstdlib>
#include <ctime>
int main() {
srandom(time(NULL));
int x = random(); }
/* C++ cin, cout */
int main() {
int x = 0, inum;
cin >> inum; /* IN */
x += inum;
cout << x << endl; }

16. First Assignment – Guess Number
DUE: midnight (23:59:59), Sep. 19 (Wed)
Submit to
Submit: student_id.tar includes
guess.cpp, io.cpp, guess.h, Makefile, Readme.txt
guess.cpp: #include “guess.h”, main(), check()
io.cpp: getNum(), printCongrats()
guess.h: declare types of getNum(), printCongrats();

17. Makefile - Example Comment Variable definition target: dependency_list
List of targets
# Makefile for hello, mem, and random
CXXFLAGS = -O3 –Wall
CXX = g++
PROGRAMS = hello mem random
all: $(PROGRAMS)
hello: hello.cpp
$(CXX) $(CXXFLAGS) –o $^
mem: mem.cpp
random: random.cpp
clean:
rm –f $(PROGRAMS)
@echo “--binaries are removed”
target: dependency_list
[TAB]command_list
: name of target
$^ : dependecy_list
First target is a default target
> make
> make all
> make random
> make clean