字符串类HString实现

最新推荐文章于 2024-07-09 18:25:15 发布

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最新推荐文章于 2024-07-09 18:25:15 发布

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文章标签：数据结构与算法

原文链接：http://www.cnblogs.com/chio/archive/2007/06/10/777893.html

本文介绍了自定义字符串类HString的设计与实现过程，包括构造、析构、赋值、拼接等操作，并展示了如何使用该类进行字符串查找等功能。

HString.h

1 #ifndef HSTRING_H
2 #define HSTRING_H
3
4 #include <iostream>
5 using namespace std;
6
7 const int MAX_SIZE = 128;
8
9 class HString
10 {
11 public:
12     HString();
13     HString(const HString &str);
14     HString(const char *str);
15     ~HString(){ delete [] ch; }
16
17     bool empty() const{ return len == 0 ? true : false; }
18     int length() const { return len; }
19     void strClear(HString &str){ len = 0; ch[0] = '\0'; }
20     char *toArray() { return ch; }
21
22     char &operator[](int i) const;
23     bool operator!(){ return empty(); }
24     HString &operator=(const HString &str);
25     HString &operator+(const HString &str);
26     HString &operator+=(const HString &str);
27
28     HString &copy(const HString &str);
29     int find(HString &pat);
30     int find(char *pa);
31
32     void print();
33
34
35
36 private:
37     char *ch;
38     int len;
39
40 };
41
42 #endif

HString.cpp

  1 #include "HString.h"
  2
  3 HString::HString()
  4 {
  5     ch = new char[MAX_SIZE + 1];//tail is '\0'
  6     if(ch == NULL)
  7     {
  8         cerr << "Allocation failed! \n";
  9         exit(-1);
10     }
11
12     len = 0;
13     ch[0] = '\0';
14 }
15
16 HString::HString(const HString &str)
17 {
18     ch = new char[MAX_SIZE + 1];
19     if(ch == NULL)
20     {
21         cerr << "Allocation failed! \n";
22         exit(-1);
23     }
24
25     int i;
26     len = str.length();
27     for(i = 0; i < len; i++)
28     {
29         ch[i] = str[i];
30     }
31     ch[len] = '\0';
32 }
33
34 HString::HString(const char *str)
35 {
36     ch = new char[MAX_SIZE + 1];
37     if(ch == NULL)
38     {
39         cerr << "Allocation failed! \n";
40         exit(-1);
41     }
42
43     int i = 0;
44     while(str[i] != '\0')
45     {
46         i++;
47     }
48
49
50     len = i;
51
52     for(i = 0; i < len; i++)
53     {
54         ch[i] = str[i];
55     }
56     ch[len] = '\0';
57 }
58
59 void HString::print()
60 {
61     cout << len << " elements: ";
62     for(int i = 0; i < len; i++)
63     {
64         cout << ch[i] << " ";
65     }
66
67     cout << endl;
68 }
69
70
71 char &HString::operator[](int i) const
72 {
73     if(i < 0 || i > len)
74     {
75         cerr << "Invailed index! \n";
76         exit(-1);
77     }
78
79     return ch[i];
80 }
81
82 int HString::find(HString &pat)
83 {
84     char *pa = pat.toArray();
85
86     if(*pa == '\0' || empty())
87     {
88         cerr << "Src or pattern string NULL \n";
89         exit(-1);
90     }
91
92     int i = 0, j = 0;
93
94     while(i < len && j < pat.length())
95     {
96         if(ch[i] == pa[j])
97         {
98             i++;
99             j++;
100         }
101         else
102         {
103             i = i - j + 1;
104             j = 0;
105         }
106         //cout << i << ": " << ch[i] << " " << j << " " << pa[j] << endl;
107
108     }
109
110     if(j >= pat.length())
111         return i - j;
112     else
113         return -1;
114 }
115
116
117 int HString::find(char *pa)
118 {
119     HString pat(pa);
120     return find(pat);
121
122 }
123
124 HString &HString::operator=(const HString &str)
125 {
126     return this->copy(str);
127 }
128
129
130 HString &HString::operator+=(const HString &str)
131 {
132     if(str.empty())
133         return *this;
134
135     if(len + str.length() > MAX_SIZE)
136     {
137         cerr << "cancat string too long \n";
138         exit(-1);
139     }
140
141     for(int i = 0; i < str.length(); i++)
142     {
143         ch[len + i] = str[i];
144     }
145     ch[len + str.length()] = '\0';
146
147     len = len + str.length();
148
149     return *this;
150 }
151
152 HString &HString::operator+(const HString &str)
153 {
154     HString *newStr = new HString(*this);
155     (*newStr) += str;
156
157     return *newStr;
158 }
159
160 HString &HString::copy(const HString &str)
161 {
162     if(&str == this)
163         return *this;
164
165     delete [] ch;
166     ch = new char[MAX_SIZE + 1];
167     if(ch == NULL)
168     {
169         cerr << "Allocation failed \n";
170         exit(-1);
171     }
172
173     len = str.length();
174     for(int i = 0; i < len; i++)
175     {
176         ch[i] = str[i];
177     }
178
179     return *this;
180 }
181
182

main.cpp

1 #include <iostream>
2 #include "HString.h"
3 using namespace std;
4
5 int main()
6 {
7     HString str("abcdefe");
8     str.print();
9
10     HString pat("de");
11
12     pat.print();
13     cout << str.find(pat) << endl;
14     cout << str.find("cd") << endl;
15
16 //    str = pat;
17 //    str.print();
18
19     str += pat;
20     str.print();
21
22     HString ns;
23     ns = str + pat;
24     ns.print();
25
26
27     return 0;
28
29 }

转载于:https://www.cnblogs.com/chio/archive/2007/06/10/777893.html