static void afis_bin(unsigned int n,int nb)
{
	int i=0,k=0;
	char val_b[32];
	if ((n > 0)&&(n <= 255))
		k=8;
	if ((n > 255)&&(n <= 65535))
		k=16;
	if ((n > 65535)&&(n <= 2147483646))
		k=32;
	if (nb > 0)
		k=nb;
	if (n > 2147483646){
		k=0;
		cout << "\nNumar prea mare";
	}
	for (i=0; i < k; i++){
		if (n%2==0)
			val_b[k-1-i]='0';
		else
			val_b[k-1-i]='1';
		n=n/2;
	}
	// afisare binara
	for (i=0; i < k; i++){
		if (val_b[i]=='0')
			cout << char(176) << " ";
		else
			cout << char(219) <<  " ";
	}
	// prompter pe prima pozitie
	for (i=0;i < (2*k+1); i++){
			cout<<"\b";
	}
}