1. ASEE / GradSWE C++ Workshop
While we’re waiting…
Follow the “Getting Started” directions at
Open Visual Studio from the Start menu:
Start / All Programs / Software Development Tools / Visual Studio 2013 / Visual Studio 2013

2. ASEE C++ Workshop
Aaron Bevill

3. Common Programming Languages
Compiled
Fortran C
C++ C#
Java
Interpreted
bash
C shell
Perl
make
Python
MatLab R
SPSS
scientific calculation
www

4. Overview Syntax, arithmetic, and variables Blocks and scope
Flow control: if, else, and for
Vectors and arrays
Functions
Comprehensive example
Further reading

5. Compiling and Running C++
Visual Studio
Create an empty Visual C++ project
Add a new source file *.cpp
Write source
Build / run
Linux Terminal
Create and edit source file *.cpp
Compile:
g++ source.cpp -o executable
Execute:
./executable

6. Basic Syntax // import std::cout as cout: #include <iostream>
using namespace std;
int main() {
cout << "hello world" << endl;
return 0; }

7. Arithmetic Operators #include <math.h> // pow // in main:
cout << << endl;
cout << << endl;
cout << 4 * 3 << endl;
cout << 24 / 5 << endl;
cout << 24 % 5 << endl;
cout << pow(2,3) << endl;

8. Variables // in main: //declare and assign
//variables before using them
int x;
x = 2;
double y = 2.;
cout << x / 2 << endl;
cout << y / 2 << endl;

9. Variable Types int 7 11 float 0.4 2e6 1. double 0.4 2e6 1.
bool true false
char 'a' 'f'

10. C++ vs MatLab Use pow(x,y) for an exponent
A decimal or scientific notation (1E4) indicates a floating point constant
Use ^ for an exponent
All numbers are assumed to be floating point

11. Blocks and Scope int x = 2; { int y = 3;
cout << x << endl;
cout << y << endl; }
// y is no longer in scope

12. Flow Control---conditionals
int x = 5;
if(x < 0) {
cout << "x is small" << endl; }
else
cout << "x is large" << endl;

13. Example 0: Impact Distance
in a new project:
define constants
G = m/s2
VX, VY0 (guess)
calculate impact
print impact state
is 100 < x < 120?
use if, else if, else
GOAL: Find initial velocities such that 100 < x < 120
5 minutes

14. Vectors and Arrays // preamble for vector: #include<vector>
using namespace std;
// array, length 3:
int x[3] = {1, 2, 3};
cout << x[0] << x[1] << x[2];
// vector, length 3:
vector<int> y(3, 4);
cout << y[0] << y[1] << y[2];

15. Arrays vs Vectors
An array is a direct allocation of memory for a fixed number of objects
cannot be resized
possible to “seg fault” from indexing error
A vector is a coder-friendly wrapper on an array, implemented using templating
it can be resized
also possible to seg fault

16. Flow Control---for loops
vector<double> x(4,8);
// initialize; condition; increment
for(int i = 0; i < x.size(); i++) {
cout << x[i] << endl; }

17. Example 1: Multiple Projectiles
define constants
G, VX
list of VY0
for each value of VY0
calculate impact
print impact state
is 100 < x < 120?
GOAL: Find initial velocities such that 100 < x < 120
5 minutes

18. Functions // first, define or declare the function
double abs1(double x) {
if(x < 0.)
return -1 * x; }
return x;
// then use it in main() :
cout << abs1(-5) << endl;

19. Example 2: Projectile Function
create a function range(vx, vy0) that returns the impact x
call that function inside the for loop
GOAL: Find initial velocities such that 100 < x < 120
3 minutes

20. Further Reading---Pointers//
// a pointer is the memory address of another variable
int x = 4;
// declare with a *
int * x_pointer;
// reference x to get a pointer to it
x_pointer = & x;
// de-reference x_pointer to retrieve the value
cout << *x_pointer << endl;
// or view the address
cout << x_pointer << endl;

21. Further Reading---File I/O//
#include <iostream>
#include <fstream>
using namespace std;
int main () {
ofstream myfile;
myfile.open ("example.txt");
myfile << "Writing this to a file.\n";
myfile.close();
return 0; }

22. Further Reading---Classes (OOP)
A class brings together data and functions that act on that data. For example, you could create a class ChessPiece with integers x and y (the position on the board, or -1 if captured), kind (a flag to indicate pawn, rook, etc) and color (a flag for black or white). The ChessPiece class could have functions move_to(x, y) to move it and capture() to capture it. These functions use and manipulate the data. A “constructor” function is implemented to create ChessPiece objects.
We can declare and initialize ChessPiece “objects” using the constructor. For example, the white rook at position (0,0) is an object:
const int ROOK=4, WHITE=1; // define flag constants
ChessPiece white_left_rook(0, 0, ROOK, WHITE);
white_left_rook.move_to(4, 0);
white_left_rook.capture();

23. Example 3: Estimating Pi
See
create function:
bool inside(x, y)
returns true if (x,y) is in the unit circle
sample 105 points (x, y)
call inside(x, y) to count how many are inside a unit circle
compare fraction inside circle to pi / 4
GOAL: Find the fraction of random x,y points
0 < x < 1
0 < y < 1
that fall in a unit circle
8 minutes

24. Advanced Syntax Exercises
Guess the output!
Questions?

25. inline operations int x = 509; x += 6; cout << x << endl;

26. matrices
// 2D, 3D, etc. data structures can be created using arrys, vectors, or classes
double eye[2][2] = { {1., 0.}, {0., 1.} };
cout << eye[0][0] << endl;
vector< vector<double> > mat3(2, vector<double>(2,3.));
cout << mat3[0][0] << endl;
// class example omitted for brevity

27. passing by reference void increment_both(int x, int & y) { x++; y++; }//
void increment_both(int x, int & y) {
x++;
y++; }
// in main():
int x=0, y=0;
increment_both(x, y);
cout << x << endl;
cout << y << endl;

28. for-continue-break char words[] = "wrcl cmbqsa";
for(int i = 0; i < 11; i++) {
if(words[i] == 'c')
continue; }
if(words[i] == 'b')
break;
cout << words[i] << endl;

29. formatted I/O // see http://www.cprogramming.com/tutorial/iomanip.html
std::cout << setprecision(3) << ;

30. inline if-else int x = 4; int y = (x < 7) ? 1 : -1;
cout << y << endl;

31. multi-line comments /* comments can span multiple lines
using the slash-asterisk
and asterisk-slash
*/ cout << "this is outside the comment" << endl;

32. throw and try-catch //
try {
throw 20; }
catch (int e)
cout << "caught excetpion number " << e << endl;
try { throw 30; }
if(e != 20) { throw; }