A combinational circuit is one of the fundamental elements in digital circuits, containing electronic computers. W.A. Davis presented a new approach to the problem of assigning binary input codes so that the combinational circuits necessary to realize the given output functions may be minimized. This paper has derived an algorithm for determining the actual cost of a given assignment scheme in Davis method. First, the combinations of partitions realizing the output functions are obtained and then those among them implementing all of the output functions are found by using a table. In consequence it has been proved that by this algorithm the process of the assignment in a schcme with 16 states and 3 determined partitions can be reduced to 1/10$^{6}$ .