I am a student in NCTU, Taiwan. This is a game code from my T.A. that is a intro. to a c++ game simple. I'm just a beginner. Can anyone give me some instruct of this code? I really want to learn.

Thanks a lot!

//////////////////////////////////////////////////////////////////////////

#define _WIN32_WINNT 0x0501
#include <windows.h>
#include <iostream>
#include <time.h>
using namespace std;
int width = 55;
int height = 35;
const float maxSpeed = 1.8f;
const int delay = 50;
HANDLE hOut;
struct pad
{
float x, y;
int size;
float ox, oy;
float vx;
pad(int x1, int y1, int size1)
{
x = float(x1);
y = float(y1);
size = size1;
ox = float(x1);
oy = float(y1);
}
void draw()
{
COORD p;
p.X = int(ox)-size ;
p.Y = int(oy);
SetConsoleCursorPosition( hOut, p );
for (int i = -size; i < size; ++i)
cout << ' ';
p.X = int(x) - size;
p.Y = int(y);
SetConsoleCursorPosition( hOut, p );
SetConsoleTextAttribute( hOut, 10 );
for (int i = -size; i < size; ++i)
cout << '=';
SetConsoleTextAttribute( hOut, 15 );
ox = x;
oy = y;
}
};
struct ball
{
float x, y, ox, oy;
float vx, vy;
ball(int x2, int y2)
{
x = float( x2 );
y = float( y2 );
ox = float( x );
oy = float( y );
vx = vy = 0;
}
void draw()
{
COORD p;
p.X = int(ox);
p.Y = int(oy);
SetConsoleCursorPosition( hOut, p );
cout << ' ';
p.X = int(x);
p.Y = int(y);
SetConsoleCursorPosition( hOut, p );
SetConsoleTextAttribute( hOut, 12 );
cout << '0';
SetConsoleTextAttribute( hOut, 15 );
ox = x;
oy = y;
}
};
void reset(pad &you, pad &comp, ball &b, bool &started, int &you_score, int &comp_score, int sel)
{
b.x = float( width / 2 - 1 );
b.y = float( height / 2 );
you.x = comp.x = float( width / 2 );
comp.vx = 0.0f;
b.vx = float(rand() % 3) - 1.5f;
b.vy = 1;
started = false;
COORD p;
p.X = 0;
p.Y = height;
SetConsoleCursorPosition( hOut, p );
if(sel!=2)
cout << "\n Your score: " << you_score << "\tComp score: " << comp_score << '\n';
else
cout << "\n Player1 score: " << you_score << "\tPlayer2 score: " << comp_score << '\n';

}
int main()
{
//selecting numbers of players
int sel;
cout<<"Please enter 1 player or 2 players: "<<endl;
cin>>sel;
if(sel==2)
{
cout<<"Player 1 controls are left & right buttons"<<endl;
cout<<"Player 2 controls are 1 and 2 buttons"<<endl;
}
system ("PAUSE");
system("cls");

hOut = GetStdHandle(STD_OUTPUT_HANDLE);
srand(int(time(NULL)));
SMALL_RECT DisplayArea = {0, 0, width, height + 3};
SetConsoleWindowInfo(hOut, TRUE, &DisplayArea);
// Hide Console Cursor
CONSOLE_CURSOR_INFO ConCurInf;
ConCurInf.dwSize = 10;
ConCurInf.bVisible = false;
SetConsoleCursorInfo(hOut, &ConCurInf);
// Draw border
SetConsoleTextAttribute( hOut, 15 );
for (int i = 0; i < width - 1; ++i)
cout << '-';
for (int i = 0; i < height - 1; ++i)
{
cout << "\n|";
for (int i = 0; i < width - 3; ++i)
cout << ' ';
cout << "|";
}
cout << '\n';
for (int i = 0; i < width - 1; ++i)
cout << '-';
if(sel==2)
cout<< "\n Player1 score: 0\tPlayer2 score: 0\n";
else
cout << "\n Your score: 0\tComp score: 0\n";
for (int i = 0; i < width - 1; ++i)
cout << '-';
// End drawing border
bool started = false;
pad you(width / 2, height - 2, 4);
pad comp(width / 2, 2, 4);
ball b(width / 2 - 1, height / 2);
int you_score = 0, comp_score = 0;
// Ball's start velocity, always starts towards you
b.vx = float(rand() % 3) - 1.5f;
b.vy = 1;
comp.vx = 0;
while (true)
{
if (started)
{
// Arrow keys
if ( GetAsyncKeyState(VK_LEFT) )
{
you.x -= 2;
}
else if ( GetAsyncKeyState(VK_RIGHT) )
{
you.x += 2;
}

if(sel ==2 ) //used when there are 2 players
{
if ( GetAsyncKeyState(0x31) ) //1
{
comp.x -= 2;
}
else if ( GetAsyncKeyState(0x32) )//2
{
comp.x += 2;
}
}

else //when one player, playing with computer
{
// Move comp.x towards the ball
comp.vx -= float(comp.x - b.x) / 10.0f;
comp.vx *= 0.83f;
// Apply comp's velocity to current location
comp.x += comp.vx;
}
// Add player boundaries
if ( you.x < you.size + 1 )
{
you.x = float ( you.size + 1 );
}
else if ( you.x > width - you.size - 2 )
{
you.x = float ( width - you.size - 2 );
}
// Add comp boundaries
if ( comp.x < comp.size + 1 )
{
comp.x = float ( comp.size + 1 );
}
else if ( comp.x > width - comp.size - 2)
{
comp.x = float ( width - comp.size - 2 );
}
// Make sure ball doesn't exceed it's maximum speed
if ( b.vx < -maxSpeed )
{
b.vx = -maxSpeed;
}
else if ( b.vx > maxSpeed )
{
b.vx = maxSpeed;
}
// Apply velocity to balls current location
b.x += b.vx;
b.y += b.vy;
// Check if ball is hitting your pad
if ( b.y >= you.y - 1 && b.y <= you.y + 1 )
{
if (b.x > you.x - you.size && b.x < you.x + you.size)
{
b.vy *= -1;
b.vx += float(b.x - you.x) / 3;
b.y = you.y - 1;
}
}
// Check if ball is hitting the computer pad
if ( b.y <= comp.y + 1 && b.y >= comp.y - 1 )
{
if (b.x > comp.x - comp.size && b.x < comp.x + comp.size)
{
b.vy *= -1;
b.vx += float(b.x - comp.x) / 3;
b.y = comp.y + 1;
}
}
// Check if ball has gone out of boundaries (a player won/lost)
if ( b.y >= height )
{
++comp_score;
reset( you, comp, b, started, you_score, comp_score, sel );
}
else if ( b.y <= 0 )
{
++you_score;
reset( you, comp, b, started, you_score, comp_score, sel );
}
if ( b.x <= 1 )
{
b.vx *= -1;
b.x = 1.0f;
}
else if ( b.x >= width - 3 )
{
b.vx *= -1;
b.x = float( width - 3 );
}
}
else
{
// Wait for user to press the space bar
COORD p;
p.X = int ( width / 2 - 16 );
p.Y = int ( height / 1.5f );
SetConsoleCursorPosition( hOut, p );
cout << "Press the space bar to start . .";
if ( GetAsyncKeyState(VK_SPACE) )
{
COORD p;
p.X = int ( width / 2 - 16 );
p.Y = int ( height / 1.5f );
SetConsoleCursorPosition( hOut, p );
cout << " ";
started = true;
}
}
// Draw all objects
you.draw();
comp.draw();
b.draw();
// Delay
Sleep(delay);
}
}