1 #include <assert.h>
2 #include <ctype.h>
3 #include <iostream>
4 using namespace std;
5
6 template<class Type>
7 struct genListNode
8 {
9 int utype;
10 union {
11 int ref;
12 Type value;
13 genListNode<Type>* hlink;
14 }info;
15 genListNode<Type>* tlink;
16 genListNode()
17 {
18 utype = 0;
19 info.ref = 0;
20 tlink = 0;
21 }
22 };
23
24 #define maxSize 100
25 template<class Type>
26 class generalized_list
27 {
28 private:
29 genListNode<Type>* first;
30 public:
31 generalized_list();
32 ~generalized_list();
33 void create_list();
34 Type get_sum();
35 private:
36 char list_name[maxSize];
37 genListNode<Type>* list_ptr[maxSize];
38 int list_num;
39 int search_list_name(char chr);
40 void create_sub_list(genListNode<Type>* &ls);
41 void remove_sub_list(genListNode<Type>* &ls);
42 };
43
44 template<class Type>
45 generalized_list<Type>::generalized_list()
46 {
47 first = new genListNode<Type>;
48 list_num = 0;
49 assert(first != 0);
50 }
51
52 template<class Type>
53 generalized_list<Type>::~generalized_list()
54 {
55 remove_sub_list(first);
56 list_num = 0;
57 }
58
59 template<class Type>
60 int generalized_list<Type>::search_list_name(char chr)
61 {
62 for(int i = 0; i < list_num; i++)
63 if(chr == list_name[i])
64 return i;
65 return -1;
66 }
67
68 template<class Type>
69 void generalized_list<Type>::create_sub_list(genListNode<Type>* &ls)
70 {//新建一个广义表，以这种形式输入："D(B(a,b),C(u,E(x,y,z)),A(#));"
71 char ch;
72 cin >> ch;
73 if(isalpha(ch) && isupper(ch) || ch == '('){
74 ls = new genListNode<Type>;
75 ls->utype = 2;
76 if(isalpha(ch) && isupper(ch)){
77 //表名处理
78 int pos;
79 pos = search_list_name(ch);
80 if(pos >= 0){//该子表已出现过
81 list_ptr[pos]->info.ref++;
82 ls->info.hlink = list_ptr[pos];
83 cin >> ch;
84 if(ch != '('){
85 cerr << "输入格式有误！表名之后必须是\'(\'！" << endl;
86 exit(-1);
87 }
88 int flag = 1;
89 while(flag > 0){//该子表已出现过，把该表的元素读掉
90 cin >> ch;
91 if(ch == '(')
92 flag++;
93 else if(ch == ')')
94 flag--;
95 else
96 ;
97 }
98 }else{//该子表未出现过
99 //建立子表的附加头结点
100 ls->info.hlink = new genListNode<Type>;
101 ls->info.hlink->utype = 0;
102 ls->info.hlink->info.ref = 1;
103
104 list_name[list_num] = ch;
105 list_ptr[list_num] = ls->info.hlink;
106 list_num++;
107 cin >> ch;
108 if(ch != '('){
109 cerr << "输入格式有误！表名之后必须是\'(\'！" << endl;
110 exit(-1);
111 }
112 create_sub_list(ls->info.hlink->tlink);//递归建子表
113 }
114 }//表名处理结束
115 create_sub_list(ls);//递归建后续表
116 }else if(ch == ',')
117 create_sub_list(ls->tlink);
118 else if(ch == ')')
119 ls->tlink = NULL;
120 else if(ch == '#'){
121 ls = NULL;
122 cin >> ch;
123 }else if(ch == ';')
124 return ;
125 else{
126 cin.putback(ch);
127 Type temp;
128 cin >> temp;
129 ls = new genListNode<Type>;
130 ls->utype = 1;
131 ls->info.value = temp;
132 create_sub_list(ls);
133 }
134 }
135
136 template<class Type>
137 void generalized_list<Type>::remove_sub_list(genListNode<Type>* &ls)
138 {
139 ls->info.ref--;
140 if(ls->info.ref <= 0){
141 genListNode<Type>* p;
142 while(ls->tlink != NULL){
143 p = ls->tlink;
144 if(p->utype == 2){
145 remove_sub_list(p->info.hlink);
146 if(p->info.hlink->info.ref <= 0)
147 delete p->info.hlink;
148 }
149 ls->tlink = p->tlink;
150 delete p;
151 }//end while
152 }//end if
153 }
154
155 template<class Type>
156 void generalized_list<Type>::create_list()
157 {
158 cout << "以下面的形式输入广义表：D(B(a,b),C(u,(x,y,z)),A(#));" << endl;
159 create_sub_list(first->tlink);
160 genListNode<Type> *p, *q;
161 p = first;
162 q = first->tlink;
163 first = q->info.hlink;
164 first->utype = 0;
165 first->info.ref = 0;
166 delete p;
167 delete q;
168 }
169
170 template<class Type>
171 Type generalized_list<Type>::get_sum()
172 {
173 Type sum = 0;
174 genListNode<Type>* p;
175 for(int i = 0; i < list_num; i++){
176 p = list_ptr[i];
177 for(; p != NULL; p = p->tlink)
178 if(p->utype == 1)
179 sum += p->info.value;
180 }
181 return sum;
182 }
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