第四十课字符串类的创建（下）

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去掉字符串两端的空白：

DTString.h更新如下：

 1 #ifndef DTSTRING_H
 2 #define DTSTRING_H
 3 
 4 #include "Object.h"
 5 
 6 namespace DTLib
 7 {
 8 
 9 class String : Object
10 {
11 protected:
12     char* m_str;
13     int m_length;
14 
15     void init(const char* s);
16     bool equal(const char* l, const char* r, int len) const;
17 public:
18     String();
19     String(char c);
20     String(const char* s);
21     String(const String& s);
22 
23     int length() const;
24     const char* str() const;
25 
26     bool startWith(const char* s) const;
27     bool startWith(const String& s) const;
28     bool endOf(const char* s) const;
29     bool endOf(const String& s) const;
30 
31     String& insert(int i, const char* s);
32     String& insert(int i, const String& s);
33 
34     String& trim();
35 
36     char& operator [] (int i);
37     char operator [] (int i) const;
38 
39     bool operator == (const String& s) const;
40     bool operator == (const char* s) const;
41 
42     bool operator != (const String& s) const;
43     bool operator != (const char* s) const;
44 
45     bool operator > (const String& s) const;
46     bool operator > (const char* s) const;
47 
48     bool operator < (const String& s) const;
49     bool operator < (const char* s) const;
50 
51     bool operator >= (const String& s) const;
52     bool operator >= (const char* s) const;
53 
54     bool operator <= (const String& s) const;
55     bool operator <= (const char* s) const;
56 
57     String operator + (const String& s) const;
58     String operator + (const char* s) const;
59     String operator += (const String& s);
60     String operator += (const char* s);
61 
62     String& operator = (const String& s);
63     String& operator = (const char* s);
64     String& operator = (char c);
65 
66     ~String();
67 };
68 
69 }
70 
71 
72 #endif // DTSTRING_H

DTString.cpp更新如下：

  1 #include <cstring>
  2 #include <cstdlib>
  3 #include "DTString.h"
  4 #include "Exception.h"
  5 
  6 using namespace std;
  7 
  8 namespace DTLib
  9 {
 10 
 11 void String::init(const char* s)
 12 {
 13     m_str = strdup(s);
 14 
 15     if( m_str )
 16     {
 17         m_length = strlen(m_str);
 18     }
 19     else
 20     {
 21         THROW_EXCEPTION(NoEnoughMemoryException, "No memory to create string object ...");
 22     }
 23 }
 24 
 25 bool String::equal(const char* l, const char* r, int len) const
 26 {
 27     bool ret = true;
 28 
 29     for(int i = 0; i < len && ret; i++)
 30     {
 31         ret = ret && (l[i] == r[i]);
 32     }
 33 
 34     return ret;
 35 }
 36 
 37 String::String()
 38 {
 39     init("");
 40 }
 41 
 42 String::String(const char* s)
 43 {
 44     init(s ? s : "");   //空指针就转换成空字符串
 45 }
 46 
 47 String::String(const String& s)
 48 {
 49     init(s.m_str);
 50 }
 51 
 52 String::String(char c)
 53 {
 54     char s[] = {c, '\0'};
 55 
 56     init(s);
 57 }
 58 
 59 int String::length() const
 60 {
 61     return m_length;
 62 }
 63 
 64 const char* String::str() const
 65 {
 66     return m_str;
 67 }
 68 
 69 bool String::startWith(const char* s) const
 70 {
 71     bool ret = ( s != NULL );
 72 
 73     if( ret )
 74     {
 75         int len = strlen(s);
 76 
 77         ret = (len < m_length) && equal(m_str, s, len);
 78 
 79     }
 80 
 81     return ret;
 82 }
 83 
 84 bool String::startWith(const String& s) const
 85 {
 86     return startWith(s.m_str);
 87 }
 88 
 89 bool String::endOf(const char* s) const
 90 {
 91     bool ret = ( s != NULL );
 92 
 93     if( ret )
 94     {
 95         int len = strlen(s);
 96 
 97         char* str = m_str + (m_length - len);
 98 
 99         ret = (len < m_length) && equal(str, s, len);
100 
101     }
102 
103     return ret;
104 }
105 
106 bool String::endOf(const String& s) const
107 {
108     return endOf(s.m_str);
109 }
110 
111 String& String::insert(int i, const char* s)
112 {
113     if( (0 <= i) && (i <= m_length) )
114     {
115         if( ( s != NULL) && ( s[0] != '\0' ) )
116         {
117             int len = strlen(s);
118             char* str = reinterpret_cast<char*>(malloc(m_length + len + 1));
119 
120             if( str != NULL )
121             {
122                 strncpy(str, m_str, i);
123                 strncpy(str + i, s, len);
124                 strncpy(str + i + len, m_str + i, m_length - i);
125 
126                 str[m_length + len] = '\0';
127 
128                 free(m_str);
129 
130                 m_str = str;
131                 m_length = m_length + len;
132             }
133             else
134             {
135                 THROW_EXCEPTION(NoEnoughMemoryException, "No memory to create str object...");
136             }
137         }
138     }
139     else
140     {
141         THROW_EXCEPTION(IndexOutOfBoundsException, "parameter i is invalid...");
142     }
143 
144     return *this;
145 }
146 
147 String& String::insert(int i, const String& s)
148 {
149     return insert(i, s.m_str);
150 }
151 
152 String& String::trim()
153 {
154     int b = 0;
155     int e = m_length - 1;
156 
157     while( m_str[b] == ' ')b++;
158     while( m_str[e] == ' ')e--;
159 
160     if( b == 0 )
161     {
162         m_str[e + 1] = '\0';
163 
164         m_length = e + 1;
165     }
166     else
167     {
168         for(int i = 0,j = b; j <= e; i++, j++)
169         {
170             m_str[i] = m_str[j];
171         }
172 
173         m_str[e - b + 1] = '\0';
174         m_length = e - b + 1;
175     }
176 
177     return *this;
178 }
179 
180 char& String::operator [] (int i)
181 {
182     if( (0 <= i) && (i < m_length) )
183     {
184         return m_str[i];
185     }
186     else
187     {
188         THROW_EXCEPTION(IndexOutOfBoundsException, "parameter i is invalid ...");
189     }
190 }
191 
192 char String::operator [] (int i) const
193 {
194     return (const_cast<String&>(*this))[i];
195 }
196 
197 bool String::operator == (const String& s) const
198 {
199     return ( strcmp(m_str, s.m_str) == 0 );
200 }
201 
202 bool String::operator == (const char* s) const
203 {
204     return ( strcmp(m_str, s ? s : "") == 0 );
205 }
206 
207 bool String::operator != (const String& s) const
208 {
209     return !(*this == s);
210 }
211 
212 bool String::operator != (const char* s) const
213 {
214     return !(*this == s);
215 }
216 
217 bool String::operator > (const String& s) const
218 {
219     return (strcmp(m_str, s.m_str) > 0);
220 }
221 
222 bool String::operator > (const char* s) const
223 {
224     return (strcmp(m_str, s ? s : "") > 0);
225 }
226 
227 bool String::operator < (const String& s) const
228 {
229     return (strcmp(m_str, s.m_str) < 0);
230 }
231 
232 bool String::operator < (const char* s) const
233 {
234     return (strcmp(m_str, s ? s : "") < 0);
235 }
236 
237 bool String::operator >= (const String& s) const
238 {
239     return (strcmp(m_str, s.m_str) >= 0);
240 }
241 
242 bool String::operator >= (const char* s) const
243 {
244     return (strcmp(m_str, s ? s : "") >= 0);
245 }
246 
247 bool String::operator <= (const String& s) const
248 {
249     return (strcmp(m_str, s.m_str) <= 0);
250 }
251 
252 bool String::operator <= (const char* s) const
253 {
254     return (strcmp(m_str, s ? s : "") <= 0);
255 }
256 
257 String String::operator + (const String& s) const
258 {
259     return (*this + s.m_str);
260 }
261 
262 String String::operator + (const char* s) const
263 {
264     String ret;
265 
266     int len = m_length + strlen(s ? s : "");
267 
268     char* str = reinterpret_cast<char*>(malloc(len + 1));
269 
270     if( str )
271     {
272         strcpy(str, m_str);
273         strcat(str, s ? s : "");
274 
275         free(ret.m_str);
276 
277         ret.m_str = str;
278         ret.m_length = len;
279     }
280     else
281     {
282         THROW_EXCEPTION(NoEnoughMemoryException, "No memory to create str object...");
283     }
284 
285     return ret;
286 }
287 String String::operator += (const String& s)
288 {
289     return (*this = *this + s.m_str);
290 }
291 
292 String String::operator += (const char* s)
293 {
294     return (*this = *this + s);
295 }
296 
297 String& String::operator = (const String& s)
298 {
299     return (*this = s.m_str);
300 }
301 
302 String& String::operator = (const char* s)
303 {
304     if( m_str != s )
305     {
306         char* str = strdup(s ? s: "");
307 
308         if( str )
309         {
310             free(m_str);
311 
312             m_str = str;
313             m_length = strlen(m_str);
314         }
315         else
316         {
317             THROW_EXCEPTION(NoEnoughMemoryException, "No memory to create str object...");
318         }
319     }
320 
321     return *this;
322 }
323 
324 String& String::operator = (char c)
325 {
326     char s[] = {c, '\0'};
327 
328     return (*this = s);
329 }
330 
331 String::~String()
332 {
333     free(m_str);
334 }
335 
336 }

测试程序如下：

 1 #include <iostream>
 2 #include "DTString.h"
 3 
 4 using namespace std;
 5 using namespace DTLib;
 6 
 7 
 8 
 9 int main()
10 {
11     String s = "D.T.Software";
12 
13     cout << s.startWith("D.T.") << endl;
14     cout << s.endOf("Software") << endl;
15 
16     for(int i = 0; i < s.length(); i++)
17     {
18         cout << s[i] << endl;
19     }
20 
21     String s1 = "";
22     s1.insert(0, "D.T.");
23     s1.insert(4, "Software");
24 
25     cout << s1.str() << endl;
26 
27     String s2 = "   abc   ";
28 
29     if( s2.trim().insert(0, "D.T.").endOf("abc") && s2.startWith("D.T.") )
30     {
31         cout << s2.str() << endl;
32     }
33 
34 
35     return 0;
36 }

运行结果如下：

第四十课 字符串类的创建（下）

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第四十课字符串类的创建（下）