//Program bases
#include <stdio.h>
#include <conio.h>
#include <math.h>
#define base 2

int i, n;
int array[100];
char c;
double d;

void decimal(void);
void binario(void);

main ()
{
     textcolor (9);
     textbackground (1);
     do
       {
       clrscr ();
       puts ("Escoje una opci¢n: ");
       puts ("");
       puts ("  a) Base a decimal.");
       puts ("  b) Decimal a base.");
       gotoxy (20,1);
       textcolor (15); clreol ();
       c = getche ();
       }
       while (c != 'a' && c!= 'b');
     textcolor (9);  clrscr ();
     printf ("Teclea el n£mero: ");
     textcolor (15); clreol ();
       if (c == 'a')
	  decimal();
	  else
	  binario();
       getch ();
     return 0;
}

void decimal(void){

     for (i=1; array[i-1]!= -35 ; i++)
	 {
	 array[i] = getche() -48;
	 if ((array[i] == -40) && (i != 1))
	    {
	    gotoxy (wherex(), wherey()) ;
	    clreol();
	    i-= 2;
	    }
	 if ((array[i] == -40) && (i == 1))
	    i --;
	 if (array [i] == -3 && i == 1 && array[0] != 1)
	    {
	    array [0]= 1;
	    i--;
	    }
	 if ((((array[i] < 0) || (array[i] >= base))
	    && array[i] != -35
	    && array[i] != -40)
	    || (array[i] == -3 && i != 1))
	    {
	    gotoxy (wherex()- 1, wherey());
	    clreol ();
	    i--;
	    sound (500);
	    delay (30);
	    nosound ();
	    printf ("\a");
	    }
	 }
     puts ("");
     i-= 2;
     n= i;
     for (; i>0; i--)
	 d += pow(base,n-i)*array[i];
     if (array [0] == 1)
	 d *= -1;
     printf ("\n%1.0f", d);
}

void binario(void)
{
     scanf ("%d", &n);
     for (i=0; n>0; i++)
	 {
	 array[i] = n % base;
	 n /= base;
	 }
     for (; i>0; i--)
	 printf ("%d", array[i-1]);
}