目标(指令)失败:用户:主要Prolog Swi

Question

may(_,[],[]).
may(num(U),[est(C1,N1,NT1)|T1],[est(C1,N1,NT1)|T2]):-
   U =< NT1,
   may(num(U),T1,T2).
min(_,[],[]).
min(num(U),[est(C2,N2,NT2)|T3],[est(C2,N2,NT2)|T4]):-
    U > NT2,
    min(num(U),T3,T4).
main:-
   U is 2.0,
   mayores(num(U),
      [ est(3,"J",3.1), est(6,"P",4.5), est(7,"L",2.0), est(4,"R",1.5),
        est(2,"C",4.7), est(5,"F",2.0), est(9,"A",3.5), est(11,"K",4.8),
        est(8,"M",2.4), est(15,"S",1.5), est(17,"D",0.5), est(19,"G",2.0)
      ],
      T2), 
   menores(num(U),
      [ est(3,"J",3.1), est(6,"P",4.5), est(7,"L",2.0), est(4,"R",1.5),
        est(2,"C",4.7), est(5,"F",2.0), est(9,"A",3.5), est(11,"K",4.8),
        est(8,"M",2.4), est(15,"S",1.5), est(17,"D",0.5), est(19,"G",2.0)
      ],
      T4), 
   write(T4),
   write(T2),
   halt.
:- main.

代码需要分为不同的列表值＆lt; = 2和值> 2。但是当我将其插入IDEONE时，它给了我这个错误。

Goal (directive) failed: user:main.

Answer 1

首先，更喜欢在程序中使用Toplevel代替halt/0或write/1。因此：

t2_t4(T2, T4) :-
   Es = [ est(3,"J",3.1), est(6,"P",4.5), est(7,"L",2.0), est(4,"R",1.5),
          est(2,"C",4.7), est(5,"F",2.0), est(9,"A",3.5), est(11,"K",4.8),
          est(8,"M",2.4), est(15,"S",1.5), est(17,"D",0.5), est(19,"G",2.0)
      ],
   U is 2.0,
   mayores(num(U), Es, T2), 
   menores(num(U), Es, T4).
?- t2_t4(T2, T4).
false.

不幸的是，这失败了。为了减少故障源，请减少数据大小和目标数量。我完成了：

： -  OP(950，FY， *(。*(_(。Menores(_，[]，_/* [] */(。menores(num(u(，[EST(C2，N2，NT2(| T3]，_/* [EST(C2，N2，NT2(| T4] */(： -     u> nt2，    * menores(num(u(，t3，t4(。T2_T4(T2，T4(： -    es = [/*  est(3，" j"，3.1(，EST(6，" P"，4.5(，EST(7，" L"，2.0(，EST(4，" R"，1.5(， est(2，" C"，4.7(，EST(5，" F"，2.0(，EST(9，" A"，3.5(，EST(11，" K"，4.8(， est(8，" M"，2.4(，EST(15，" S"，1.5(，EST(17，" D"，0.5(， */         EST(19，" G"，2.0(      ]，，   u是2.0，   *  mayores(num(u(，es，t2(，   Menores(NUM(U(，ES，T4(。

因此，实际问题是menores仅针对元素较小的情况定义。如果它们相等或更高的menores失败。您也需要明确说明这一点。mayores的同样参数。为什么不将两者都放入一个谓词中？另外，无需使用num/1。

mayores_menores(_,[], [], []).
mayores_menores(U,[E|Es],[E|Mays],Mens):-
   E = est(_,_,NT),
   U =< NT,
   mayores_menores(U,Es,Mays,Mens).
mayores_menores(U,[E|Es],Mays,[E|Mens]):-
   E = est(_,_,NT),
   U > NT,
   mayores_menores(U,Es,Mays,Mens).

t2_t4x(T2, T4) :-
   Es = [ est(3,"J",3.1), est(6,"P",4.5), est(7,"L",2.0), est(4,"R",1.5),
          est(2,"C",4.7), est(5,"F",2.0), est(9,"A",3.5), est(11,"K",4.8),
          est(8,"M",2.4), est(15,"S",1.5), est(17,"D",0.5), est(19,"G",2.0)
      ],
   mayores_menores(2.0, Es, T2, T4).