PROLOG语言求 过河问题
程序运行时出现下面错误:
406 '>' or',' expected 这个错该怎么修改,急需!谢谢大家!
domains
x=real
y=real
a=real
b=real
m1=real
m2=real
m3=real
m4=real
m=real
n=real
reallist=real*
boat=real
boat1=real
f=real
Predicates
row(real,real)
change(real,real,real,real,real,real,real,real,real)
across(reallist,real,real,real)
Clauses
row(2,0).
row(0,2).
row(1,0).
row(1,1).
row(0,1).
change(x,y,m1,m2,m3,m4,a,b,0):-m1=a-x,m2=b-y,m3=3-a+x,m4=3-b+y.
change(x,y,m1,m2,m3,m4,a,b,1):-m1=a+x,m2=b+y,m3=3-a-x,m4=3-b-y.
across([0,0],1,m,n).
across([a,b],boat,m,n):-row(x,y),(x <> m;y <> n)
change(x,y,m1,m2,m3,m4,a,b,boat),
(m1=0;m1>=m2),(m3=0;m3>=m4),m2>=0,m4>=0,f=boat+1,
write('('),write(x),write('--'),write(y),write(')'),boat1=f mod 2,
across([m1,m2],boat1,x,y).
goal
across([3,3],0,0,0).