1. A carry lookahead adder, comprising: a first memristor, wherein said first memristor is connected to a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch and a tenth switch, wherein said first, second, third and fourth switches are connected in series, wherein said fifth, sixth and seventh switches are connected in series, wherein said eighth and ninth switches are connected in series, wherein a combination of said first, second, third and fourth switches is connected in parallel to a combination of said fifth, sixth and seventh switches which is connected in parallel to a combination of said eighth and ninth switches which is connected in parallel to said tenth switch; a second memristor connected in parallel to said first memristor, wherein said second memristor is connected to an eleventh switch, a twelfth switch, a thirteenth switch, a fourteenth switch, a fifteenth switch and a sixteenth switch, wherein said eleventh, twelfth and thirteenth switches are connected in series, wherein said fourteenth and fifteenth switches are connected in series, wherein a combination of said eleventh, twelfth and thirteenth switches is connected in parallel to a combination of said fourteenth and fifteenth switches which is connected in parallel to said sixteenth switch; and a third memristor connected in parallel to said second memristor, wherein said third memristor is connected to a seventeenth switch, an eighteenth switch and a nineteenth switch, wherein said seventeenth and eighteenth switches are connected in series, wherein a combination of said seventeenth and eighteenth switches is connected in parallel to said nineteenth switch.