PROLOG- LOGICAL EXPRESSION FOR ALL OF THEM

Suppose we have a database of the reigns of the Sovereign Princes of Wales in the 9th and 10th centuries. The predicate reigns is defined such that the goal reigns(X, Y, Z) is true if the prince named X reigned from year Y to year Z. The list of facts in the database looks like this.

reigns(rhodri, 844, 878).

reigns(anaruwd, 878, 916).

reigns(hywel, 916, 956).

reigns(lago-sp-idwal, 956,979).

reigns(hywel-ap-iemf, 979,985).

reigns(cadwallon, 985, 986).

reigns(marcdudd, 986, 999).

Define a rule called is-prince that given a name and a date would search the database and compare the given date against the dates of the reign.

(10)Write a Prolog program that computes the factorial of N. For example,

?- fac(4,X). will give

X = 24

?- fac(5,X). will results in

X = 120

We already have the following relationships defined.

Father (X, Y) /* X is the father of Y */

Mother(X, Y) /* X is the mother of Y */

Male(X) /* X is male */

Female(X) /* X is female */

Parent(X, Y) /* X is a parent of Y */

Diff(X, Y) /* X and Y are different */