2.1.2PR0L0G的程序 PROL0G程序一般由一组事实、规则和问题组 成。问题是程序执行的起点,称为程序的目标。 likes(bell, sports).H likes(mary, music).蕌 likes(mary, sports).H likes(jane, smith) friend (john, X): -likes(X, reading), likes(X, music) friend (john, X): -likes(X, sports), likes(X, music) ?-friend (john, Y)2.1.2 PROLOG的程序 PROLOG程序一般由一组事实、 规则和问题组 成。问题是程序执行的起点, 称为程序的目标。 likes(bell,sports). likes(mary,music). likes(mary,sports). likes(jane,smith). friend(john,X):-likes(X,reading),likes(X,music). friend(john,X):-likes(X,sports),likes(X,music). ?-friend(john,Y)