The coding given below is of a simple game in which the objective is to arrange the numbers in ascending order using direction keys. Playing the game is quite simple. Pressing the direction keys will cause the shifting of the blank space and the neighbouring numbers. The executable file can be downloaded from here : GAME

#include"stdio.h"
#include"conio.h"
#include"dos.h"
#include"time.h"
int a[4][4]={1,4,15,7,
	     8,10,2,11,
	     14,3,6,13,
	     12,9,5,32};
int b[4][4]={1,2,3,4,
	     5,6,7,8,
	     9,10,11,12,
	     13,14,15,32};
int x,y,p,q,cpos,rpos,r=0,c=1,secount=0,seconds=0,min=0,sec=0;
int error=0,error2=0,count=0,minutes=0;

//time_t t1=time(NULL);
getkey()
	{ time_t start=time(NULL);
	  time_t next;
	  union REGS i,o;
	  while(!kbhit())
	     {  next=time(NULL);
		seconds=sec+difftime(next,start);
	      /*	if(seconds>59)
		     { minutes++;
		       secount++;
		       start=time(NULL);
		     } */
		printf("%d sec\r",seconds);
	     }
	  sec=seconds;
	  i.h.ah=0;
	  int86(22,&i,&o);
	  return(o.h.ah);
	}

void display()
	 { printf("\n\n");
	   for(x=0;x<4;x++)
	    { printf("\t\t");
	      for(y=0;y<4;y++)
	       { if(a[x][y]!=32 && count==0)
		    { printf("%d",a[x][y]);
		      delay(300);
		      printf("     \t");
		    }
		  if(a[x][y]!=32 && count!=0)
		    { printf("%d",a[x][y]);
		      printf("     \t");
		    }
		  if(a[x][y]==32 && count==0)
		    { printf("%c",a[x][y]);
		      delay(300);
		      printf("     \t");
		    }
		  if(a[x][y]==32 && count!=0)
		    { printf("%c",a[x][y]);
		      printf("     \t");
		    }
	       }
	      printf("\n\n");
	    }
	 }
check()
	{ for(p=0;p<4;p++)
	   { for(q=0;q<4;q++)
	     { if(a[p][q]==b[p][q])
		 c++;
	       else
		  { c=1;
		    break;
		  }
	      }
	     if((p!=3 && a[p][q]!=b[p][q]) && (p==3 && a[p][q-1]!=b[p][q]))
	       { c=1;
		break;
	       }
	   }
	   return c;
	}
main()
	{
	  rpos=cpos=3;
	  clrscr();
	  do
	     { clrscr();
	       if(error)
		 { printf("\n\nUse the correct DIRECTION KEYS\n\n");
		   error=0;
		   count--;
		 }
	       if(error2)
		{ printf("\n\nUse only DIRECTION KEYS \n\n");
		  count--;
		  error2=0;
		}
	       if(count==0)
		  printf("\n\nINSTRUCTION : Arrange the nos. in ascending order using DIRECTION KEYS");
	       display();
	       printf("\nNO. OF MOVES : %d",count);
	       printf("\n\n\n\n\t\t\tANY TIME PRESS 'ESC' TO EXIT\n\n");
	       r=getkey();
	       count++;
	       switch(r)
		 { case 72 :
			    if(rpos!=3)
			     { a[rpos-1][cpos]=a[++rpos][cpos];
			       a[rpos][cpos]=' ';
			     }
			    else
			       error=1;
			    break;
		   case 75 :
			    if(cpos!=3)
			     { a[rpos][cpos-1]=a[rpos][++cpos];
			       a[rpos][cpos]=' ';
			     }
			    else
			      error=1;
			    break;
		   case 80 :
			    if(rpos!=0)
			     { a[rpos+1][cpos]=a[--rpos][cpos];
			       a[rpos][cpos]=' ';
			     }
			    else
			       error=1;
			    break;
		   case 77 :
			    if(cpos!=0)
			     { a[rpos][cpos+1]=a[rpos][--cpos];
			       a[rpos][cpos]=' ';
			     }
			    else
			       error=1;
			    break;
		   case 1 :
			    exit(0);
		   default :
			    error2=1;
			    break;
		 } r=0;
	     }   while(check()!=17);
	       clrscr();
	       display();
	       printf("\n\n\t\t\tCONGRATES !! PUZZLE COMPLETED. %c %c\n\n",1,1);
	       printf("\t\t\tTotal no. of moves : %d.",count);
	       printf("\t\t\tTotal time : %d sec.",seconds);
	       getch();
	       return 0;
	 }