Using 'switch' can simplify your code slightly,
void sevenseg(int val)
{
switch ( val )
{
case 0: zero(); break;
case 1: one(); break;
case 2: two(); break;
case 3: three(); break;
case 4: four(); break;
case 5: five(); break;
case 6: six(); break;
case 7: seven(); break;
case 8: eight(); break;
case 9: nine(); break;
}
}