First "big" real code I ever wrote - for my 11th grade project at Sardar Patel Vidyalaya in 2003. It is a clone of Breakout written in Turbo C++ compiled using the Borland compiler. It ran (fast) on an old Pentium with 512kb of RAM. I have come a long way since then...

DXBALL.cpp

#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
#include <dos.h>
#include <time.h>
#include <ctype.h>

class player
{private: int color,x,y,width,height,psila;
 public : player(int,int,int,int,int,int);
    void init_size(int,int,int);
	  void paint_player(int,int);
	  void unpaint_player(int,int);
	  void init_psila();
	  void paint_psila();
	  int unpaint_psila();
	  int player_size();
 };

player::player(int _color=13,int _x=300,int _y=454,int _width=72,int _height=10,int _psila=3)
{color=_color;
 x=_x;
 y=_y;
 width=_width;
 height=_height;
 psila=_psila;
 }

void player::paint_player(int _x,int _y)
{x=_x;
 y=_y;
 setfillstyle(2,color);
 bar(x,y,x+width,y+height);
 }

void player::unpaint_player(int _x,int _y)
{x=_x;
 y=_y;
 setfillstyle(2,BLACK);
 bar(x,y,x+width,y+height);
 }

void player::init_psila()
{psila=3;
 setfillstyle(2,13);
 bar(600,0,565,10);
 bar(560,0,525,10);
 }

void player::paint_psila()
{setfillstyle(2,13);
 psila++;
 if(psila==7) bar(400,0,365,10);
 if(psila==6) bar(440,0,405,10);
 if(psila==5) bar(480,0,445,10);
 if(psila==4) bar(520,0,485,10);
 if(psila==3) bar(560,0,525,10);
 if(psila==2) bar(600,0,565,10);
 }

int player::unpaint_psila()
{setfillstyle(2,BLACK);
 psila--;
 if(psila==6) bar(400,0,365,10);
 if(psila==5) bar(440,0,405,10);
 if(psila==4) bar(480,0,445,10);
 if(psila==3) bar(520,0,485,10);
 if(psila==2) bar(560,0,525,10);
 if(psila==1) bar(600,0,565,10);
 return psila;
 }

void player::init_size(int _width,int _height,int _color)
{width=_width;
 height=_height;
 color=_color;
 }

int player::player_size() { return width; }


class ball
{private: int color,radius,x,y;
 public : ball(int,int,int,int);
	  void init_size(int _radius,int _color);
	  void paint_ball(int,int);
	  void unpaint_ball(int,int);
 };

ball::ball(int _color=15,int _radius=4,int _x=335,int _y=450)
{color=_color;
 radius=_radius;
 x=_x;
 y=_y;
 }

void ball::paint_ball(int _x,int _y)
{x=_x;
 y=_y;
 setfillstyle(1,color);
 fillellipse(x,y,radius,radius);
 }

void ball::unpaint_ball(int _x,int _y)
{x=_x;
 y=_y;
 setfillstyle(1,BLACK);
 fillellipse(x,y,radius,radius);
 }

void ball::init_size(int _radius,int _color)
{color=_color;
 radius=_radius;
 }


struct HIGH_SCORE { char name[20],score[20]; };


class brick
{private: int x,y,enable,shape,destroy,height,width,bg;
 public : void init(int,int,int,int,int,int,int);
	  void hide();
	  void init_destroy();
	  void undo_destroy();
	  void paint();
	  int  is_in(int,int);
 };

void brick::init(int _x,int _y,int w,int h,int _bg,int _shape=0,int _destroy=0)  //initialize
{x=_x;
 y=_y;
 width=w;
 height=h;
 bg=_bg;
 enable=1;
 shape=_shape;
 destroy=_destroy;
 }

void brick::paint()
{if(shape) setfillstyle(10,bg);
 else setfillstyle(1,bg);
 bar(x, y, x+width-1, y+height-1);
 setcolor(WHITE);
 line(x, y, x+width-1, y);
 line(x, y, x, y+height-1);
 line(x, y+height-1, x+width-1, y+height-1);
 line(x+width-1, y+height-1, x+width-1, y);
 if(shape)
  {setfillstyle(1,RED);
   fillellipse(x+width/2,y+height/2,10,10);
   setcolor(BLACK);
   circle(x+width/2-5,y+height/2-3,1);
   circle(x+width/2+5,y+height/2-3,1);
   circle(x+width/2,y+height/2+1,1);
   pieslice(x+width/2,y+height/2+5,180,360,3);
   }
 setcolor(BLACK);
 }

int brick::is_in(int x1, int y1)
{if(x1>=x-5&&x1<=x+width+5&&y1<=y+height+5&&y1>=y-5&&destroy&&enable) return 5;
 if(x1>=x-5&&x1<=x+width+5&&y1<=y+height+5&&y1>=y+height&&enable)     return 1;
 else if(x1>=x-5&&x1<=x+width+5&&y1<=y+5&&y1>=y&&enable)              return 2;
 else if(x1<=x+width+5&&x1>=x+width&&y1>=y-5&&y1<=y+height+5&&enable) return 3;
 else if(x1>=x-5&&x1<=x&&y1>=y-5&&y1<=y+height+5&&enable)             return 4;
 return 0;
 }

void brick::hide()
{setfillstyle(1,BLACK);
 bar(x, y, x+width-1, y+height-1);
 setcolor(BLACK);
 line(x, y, x+width-1, y);
 line(x, y, x, y+height-1);
 line(x, y+height-1, x+width-1, y+height-1);
 line(x+width-1, y+height-1, x+width-1, y);
 setfillstyle(1,WHITE);
 enable=0;
 }

void brick::init_destroy() { destroy=1; }

void brick::undo_destroy() { destroy=0; }

brick array1[10][14];
player p;
ball b;
int x=300,y=460,x1=335,y1=460,angle,up_down,destroy,color_exchange=1,i1random_number,
    number_of_bricks,sound_on_off=1,irandom_number,jrandom_number,j1random_number;
long result;
int psila();
char level[]={"1"};
char flag;
void graphic_init();
void start_position();
void start_screen();
void paint_bricks1();
void paint_bricks2();
void paint_bricks3();
void paint_bricks4();
void paint_bricks5();
void del_check();
void play();
void ball_hit();
void another_play();
void end_level();
void make_sound(int);
void bonus_check();
void bonus_type();
void game_is_over();
void high_score();

void main()
{graphic_init();
 time_t t;
 srand((unsigned)time(&t));
 start_screen();
 if((flag=getch())==27)
  {closegraph();
   exit(1);
   }
 cleardevice();
 p.init_psila();
 paint_bricks1();
 start_position();
 }

void graphic_init()
{int gd=DETECT,gm;
 initgraph(&gd,&gm,"c:\\DX-BALL\\Graphic-files");
 }

void start_position()
{int s1=0;
 p.unpaint_player(x,y);
 for(int i=0;i<10;i++)
  for(int j=0;j<14;j++)
   array1[i][j].undo_destroy();//undestroy bricks
 p.init_size(72,10,13);
 b.init_size(4,15);
 setcolor(10);
 settextstyle(0,0,2);
 outtextxy(30,0,"SCORE:");
 setcolor(color_exchange);
 setfillstyle(2,color_exchange);
 outtextxy(240,0,"LEVEL");
 outtextxy(330,0,level);
 bar(0,0,20,500);//left wall
 bar(639,0,619,500);//right wall
 setcolor(BLACK);
 while(1)
  {while(!kbhit())
    {if(x==24||x==618-p.player_size()-2)
      {s1=0;
       x= (x==24)? 28:618-p.player_size()-6;
	}
      x+=s1;
      x1=x+p.player_size()/2;
      if(s1)//not freeze
       {p.paint_player(x,y);
	delay(6);
	p.unpaint_player(x,y);
	b.paint_ball(x1,y1);
	delay(4);
	b.unpaint_ball(x1,y1);
	 }
      else//freeze
       {p.paint_player(x,y);
	b.paint_ball(x1,y1);
	 }
   }//end of while (!kbhit())//
 p.unpaint_player(x,y);
 b.unpaint_ball(x1,y1);
 flag=getch();
 if(flag==27)//esc//
  {closegraph();
   exit(0);
    }
 if(flag==' ') s1=0;
 if(flag=='o'||flag=='O') sound_on_off*=-1;
 if((flag=='s'||flag=='S')&&(x>=x1-p.player_size()&&x<=x1)) play();
 if(flag==0) flag=getch();
 if(flag==77||flag==75)
  {if(flag==77) s1=4;//move right//
   if(flag==75) s1=-4;//move left//
    }
  }//end of while//
 }

void start_screen()
{char place1[]={"1"};
 destroy=0;		//0 bricks destroyed//
 result=0;		//result is 0//
 color_exchange=1;
 (*level)='1';		//level 1//
 setcolor(13);
 setfillstyle(2,0);
 bar(0,0,650,500);
 settextstyle(0,0,8);
 setcolor(10);
 outtextxy(110,20,"DX-BALL");
 settextstyle(4,0,6);
 setcolor(12);
 outtextxy(60,90,"By Pathikrit Bhowmick");
 setcolor(10);
 settextstyle(2,0,7);
 outtextxy(10,200,"Space : Stop");
 outtextxy(10,230,"S     : Shoot");
 outtextxy(10,260,"O     : Sound (On/Off)");
 outtextxy(10,290,"P     : Pause");
 outtextxy(10,320,"->    : Right");
 outtextxy(10,350,"<-    : Left");
 outtextxy(10,380,"Esc   : Exit");
 setcolor(12);
 outtextxy(10,450,"Press Any Key To Start The Game.....");
 setfillstyle(1,0);
 setcolor(2);
 bar3d(320,180,620,440,8,1);
 setcolor(12);
 settextstyle(1,0,3);            //print high score//
 outtextxy(410,185,"High Scores :-");
 setcolor(2);
 outtextxy(390,200,"-------------");
 HIGH_SCORE ezer1;
 int y=220;
 FILE *fin=fopen("high_score.txt","r");
 while(fscanf(fin,"%s %s\n",ezer1.name,ezer1.score)!=EOF)
  {setcolor(4);
   if(y==220) setcolor(12);
   outtextxy(350,y,place1);
   setcolor(2);
   if(y==220) setcolor(10);
   outtextxy(380,y,ezer1.name);
   setcolor(4);
   if(y==220) setcolor(12);
   outtextxy(530,y,ezer1.score); //end print high score//
   y+=23;
   (*place1)++;
  }
 fclose(fin);
}

void play()
{int s=0;
 while(1)
 {while(!kbhit())
  {if(x==24||x==618-p.player_size()-2)
   {s=0;
    x= (x==24)? 28:618-p.player_size()-6;
    }
   x+=s;
   if(s)
   {p.paint_player(x,y);
    delay(6);
    p.unpaint_player(x,y);
    }
   else
   {p.paint_player(x,y);
    delay(6);
    }
   del_check();
   if(y1==30||y1==460) ball_hit();//ball hits the player or the ceiling
   if(x1>=26&&x1<=30||x1<=613&&x1>=609)//ball hits the walls
   {if(sound_on_off==1)	make_sound(30);
    angle*=-1;
    }
   b.paint_ball(x1,y1);
   delay(4);
   b.unpaint_ball(x1,y1);
   y1+=up_down;
   x1+=angle;
   }//end of while(!kbhit())//
  p.unpaint_player(x,y);
  flag=getch();
  if(flag==27)//exit//
  {closegraph();
   exit(0);
   }
  if(flag==' ')s=0;//stop//
  if(flag=='p'||flag=='P')flag=getch();//pause//
  if(flag=='o'||flag=='O')sound_on_off*=-1;
  if(flag==0)             flag=getch();
  if(flag==77) s= 4;//move right
  if(flag==75) s=-4;//move left
  }//end of nonstop loop//
 }

void paint_bricks1()
{irandom_number=rand()%4;
 jrandom_number=rand()%13;
 i1random_number=rand()%4;
 j1random_number=rand()%13;
 int i,j,x=22,y=120,width=44,height=25,color=1,shap=1;
 for(i=0;i<4;i++,y+=26,x=22)
  for(j=0;j<13;j++,x+=46)
  {if(color==15) color=1;
   if(i==irandom_number&&j==jrandom_number)
   {array1[irandom_number][jrandom_number].init(x,y,width,height,15,shap);
    array1[irandom_number][jrandom_number].paint();
    }
   else if(i==i1random_number&&j==j1random_number)
   {array1[i1random_number][j1random_number].init(x,y,width,height,15,shap);
    array1[i1random_number][j1random_number].paint();
     }
   else
   {array1[i][j].init(x,y,width,height,color++);
    array1[i][j].paint();
    }
   }
 number_of_bricks=i*j;
 }

void paint_bricks2()
{irandom_number=rand()%7;
 jrandom_number=rand()%11;
 i1random_number=rand()%7;
 j1random_number=rand()%11;
 int i,j,x=26,y=80,width=40,height=25,color=1,step=0,direct=1,shap=2;
 for(i=0;i<7;i++,y+=27,step=step+42*direct,x=26+step)
  for(j=0;j<11;j++,x+=42)
  {if(i==3) direct=-1;
   if(color==15) color=1;
   if(i==irandom_number&&j==jrandom_number)
   {array1[irandom_number][jrandom_number].init(x,y,width,height,15,shap);
    array1[irandom_number][jrandom_number].paint();
    }
   else if(i==i1random_number&&j==j1random_number)
   {array1[i1random_number][j1random_number].init(x,y,width,height,15,shap);
    array1[i1random_number][j1random_number].paint();
    }
   else
   {array1[i][j].init(x,y,width,height,color++);
    array1[i][j].paint();
    }
   }
 number_of_bricks=i*j;
 }

void paint_bricks3()
{irandom_number=rand()%2;
 jrandom_number=rand()%14;
 i1random_number=rand()%2;
 j1random_number=rand()%14;
 int i,j,x=27,y=30,width=40,height=25,color=3,shap=5;
 for(i=0;i<2;i++,y+=250,x=27)
  for(j=0;j<14;j++,x+=42)
  {if(i==irandom_number&&j==jrandom_number)
   {array1[irandom_number][jrandom_number].init(x,y,width,height,15,shap);
    array1[irandom_number][jrandom_number].paint();
    }
   else if(i==i1random_number&&j==j1random_number)
   {array1[i1random_number][j1random_number].init(x,y,width,height,15,shap);
    array1[i1random_number][j1random_number].paint();
    }
   else
   {array1[i][j].init(x,y,width,height,color);
    array1[i][j].paint();
    }
   }
  for(color++,width=30,height=15,y=100,x=95;i<10;i++,color++,x=95,y+=17)
   for(j=0;j<14;j++,x+=32)
   {array1[i][j].init(x,y,width,height,color);
    array1[i][j].paint();
    }
 number_of_bricks=j+(i-1)*j;
 }

void paint_bricks5()
{irandom_number=rand()%5;
 jrandom_number=rand()%14;
 i1random_number=rand()%5;
 j1random_number=rand()%14;
 int i,j,x=26,y=90,width=40,height=25,color=1,shap=3;
 for(i=0;i<5;i++,y+=60,x=26,color++)
  for(j=0;j<14;j++,x+=42)
   {if(i==irandom_number&&j==jrandom_number)
    {array1[irandom_number][jrandom_number].init(x,y,width,height,15,shap);
     array1[irandom_number][jrandom_number].paint();
     }
    else if(i==i1random_number&&j==j1random_number)
    {array1[i1random_number][j1random_number].init(x,y,width,height,15,shap);
     array1[i1random_number][j1random_number].paint();
     }
    else
    {array1[i][j].init(x,y,width,height,color);
     array1[i][j].paint();
     }
    }
 number_of_bricks=i*j;
 }

void paint_bricks4()
{irandom_number=rand()%10;
 jrandom_number=rand()%7;
 i1random_number=rand()%10;
 j1random_number=rand()%7;
 int i,j,x=27,y=70,width=40,height=25,color=4,shap=4;
 for(i=0;i<10;i++,y+=27,x=27,color++)
  for(j=0;j<7;j++,x+=91)
  {if(i==irandom_number&&j==jrandom_number)
   {array1[irandom_number][jrandom_number].init(x,y,width,height,15,shap);
    array1[irandom_number][jrandom_number].paint();
    }
   else if(i==i1random_number&&j==j1random_number)
   {array1[i1random_number][j1random_number].init(x,y,width,height,15,shap);
    array1[i1random_number][j1random_number].paint();
    }
   else
   {array1[i][j].init(x,y,width,height,color);
    array1[i][j].paint();
    }
   }
 number_of_bricks=i*j;
 }

void del_check()
{int check;
 static char show_result[]={0};
 for(int i=0;i<10;i++)
  for(int j=0;j<14;j++)
  {check=array1[i][j].is_in(x1,y1);
   if(check)
   {if(check==1) up_down=2;
    if(check==2) up_down=-2;
    if(check==3||check==4) angle*=-1;
    array1[i][j].hide();
    if(i==irandom_number&&j==jrandom_number||i==i1random_number&&j==j1random_number) bonus_type();//bonus//
    outtextxy(135,0,show_result);
    result+=125;
    bonus_check();
    ltoa(result,show_result,10);
    setcolor(12);
    outtextxy(135,0,show_result);
    setcolor(BLACK);
    if(sound_on_off==1)
    {sound(500);
     delay(20);
     nosound();
     }
    if(++destroy==number_of_bricks) end_level(); //all bricks have been destroyd//
    }
   }
 }

int psila()
{int game_over;
 game_over=p.unpaint_psila();
 if(game_over)
 {if(sound_on_off==1) make_sound(800);
  start_position();
  }
 else game_is_over();
 return 0;
 }

void ball_hit()
{up_down=(y1==460)?(-2):(2);
 if(y1==460)
 {if(x>=x1-p.player_size()&&x<=x1)//ball hit player//
  {if(sound_on_off==1)
   {sound(900);
    delay(20);
    nosound();
     }
  if(x1==x+p.player_size()/2) angle=1;//middle hit
  else if(x+p.player_size()/2+1<=x1&&x+p.player_size()/2+15>=x1)    angle= 2;
  else if(x+p.player_size()/2+15+1<=x1&&x+p.player_size()/2+25>=x1) angle= 3;
  else if(x+p.player_size()/2+25+1<=x1&&x+p.player_size()/2+35>=x1) angle= 5;
  else if(x+p.player_size()/2-10<=x1&&x+p.player_size()/2-1>=x1)    angle=-2;
  else if(x+p.player_size()/2-25<=x1&&x+p.player_size()/2-16>=x1)   angle=-3;
  else if(x<=x1&&x+p.player_size()/2-26>=x1)            	    angle=-5;
  }
  else up_down=psila();//ball mised player//
  }
 else if(sound_on_off==1) make_sound(30);//ball mised player//
 }

void end_level()
{for(int i=0;i<10;i++)
  for(int j=0;j<14;j++)
   array1[i][j].hide();//delete bricks
 p.unpaint_player(x,y);
 x=300,y=460;//player//
 x1=335,y1=460;//ball//
 setcolor(BLACK);
 outtextxy(330,0,level);
 outtextxy(240,0,"LEVEL");
 (*level)++;
 color_exchange++;
 if(sound_on_off==1) make_sound(3000);
 destroy=0;
 delay(1000);
 if(*level=='2') paint_bricks2();
 if(*level=='3') paint_bricks3();
 if(*level=='4') paint_bricks4();
 if(*level=='5') paint_bricks5();
 if(*level=='5') paint_bricks4();
 start_position();
 }

void make_sound(int s)
{for(;s>0;s=s-30)
 {sound(s);
  delay(30);
  nosound();
  } //end of for//
 } //end of make_sound//

void bonus_check()
{if(result%10000==0)//bonus every 10,000 points//
 {if(sound_on_off==1) make_sound(300);
  p.paint_psila();
  }
 }

void bonus_type()
{int bonus_number=rand()%6;
 if(sound_on_off==1)
 {make_sound(400);
  make_sound(500);
  make_sound(600);
  make_sound(700);
  }
 switch(bonus_number)
 {case 0: p.paint_psila(); break; 	//bonus chance
  case 1: if(*level=='5') bonus_type();
	  else  end_level();
	  break;	//skip level//
  case 2: p.init_size(100,15,10);break;	//player is big//
  case 3: p.init_size(140,20,14);break;	//player is very big//
  case 4: p.init_size(180,25,9);break;	//player is very very big//
  case 5: for(int i=0;i<10;i++)		//bricks destroyer is on//
	   for(int j=0;j<14;j++)
	    array1[i][j].init_destroy();
	  b.init_size(5,4);
  }
 }

void game_is_over()
{char show_result1[]={0};
 cleardevice();
 setcolor(10);
 settextstyle(0,0,3);
 outtextxy(180,250,"Game over!!!");
 setcolor(10);
 outtextxy(100,120,"Your Score:");
 setcolor(12);
 ltoa(result,show_result1,10);
 outtextxy(420,120,show_result1);
 delay(5000);
 high_score();
 start_screen();
 delay(2000);
 if((flag=getch())==27)
 {closegraph();
  exit(0);
  }
 cleardevice();
 for(int i=0;i<10;i++)
  for(int j=0;j<14;j++)
   array1[i][j].hide();//delete bricks
 p.init_psila();
 paint_bricks1();
 x=300,y=460;//player//
 x1=335,y1=460;//ball//
 start_position();
 }

void high_score()
{char name1[20]={' '},*p=name1;
 int i,j;
 FILE *fin;
 HIGH_SCORE ezer,array[9]={0};
 fin=fopen("high_score.txt","r");
 for(i=0;fscanf(fin,"%s %s\n",array[i].name,array[i].score)!=EOF;i++);
 if(result<=atol(array[8].score))
 {fclose(fin);
  return;
  }
 ltoa(result,array[8].score,10);
 cleardevice();
 bar(0,0,650,500);
 setcolor(10);
 settextstyle(0,0,3);
 outtextxy(80,20,"New High Score !!!");
 setcolor(12);
 outtextxy(100,90,array[8].score);
 setcolor(10);
 outtextxy(50,150,"Enter Your Name :");
 setfillstyle(1,BLACK);
 bar3d(280,250,520,300,4,4);
 settextstyle(7,0,4);
 setcolor(12);
 for(i=0;i<10;)
 {*p=getch();
  if(islower(*p))
  {name1[i]=*p;
   name1[i+1]=NULL;
   outtextxy(300,250,name1);
   p++;
   i++;
   }
  if((*p==13||*p==27||i==9)&&i>0)
  {*p=NULL;
   break;
   }
  }
 strcpy(array[8].name,name1);
 fclose(fin);
 for(i=0;i<9;i++)
  for(j=0;j<8;j++)
   if(atol(array[j].score)<atol(array[j+1].score))
   {ezer=array[j];
    array[j]=array[j+1];
    array[j+1]=ezer;
    }
 fin=fopen("high_score.txt","w");
 for(i=0;i<9;i++) fprintf(fin,"%s %s\n",array[i].name,array[i].score);
 fclose(fin);
 }