1 class CMyString
2 {
3 friend std::ostream& operator<<( std::ostream& os, const CMyString& str);
4 private:
5 char* m_pData; // 私有变量保存字符串
6 public:
7 CMyString( const char* str = NULL ); // 构造函数
8 CMyString( const CMyString& str ); // 拷贝构造函数
9 ~CMyString( void ); // 析构函数
10 CMyString& operator=( const CMyString& str ); // 赋值运算符
11 CMyString operator+( const CMyString& str ); // 字符串连接
12 bool operator==( const CMyString& str ); // 判断相等
13 char operator[]( int idx ); // 数组索引
14 int getLength(); // 返回长度
15 };
1 CMyString::CMyString( const char* str )
2 {
3 if ( !str )
4 {
5 this->m_pData = 0;
6 }
7 else
8 {
9 this->m_pData = new char[ strlen( str ) + 1 ];
10 strcpy( this->m_pData, str );
11 }
12 }
13
14 CMyString::CMyString( const CMyString& str )
15 {
16 if ( !str.m_pData )
17 {
18 this->m_pData = 0;
19 }
20 else
21 {
22 this->m_pData = new char[ strlen( str.m_pData ) + 1 ];
23 strcpy( this->m_pData, str.m_pData );
24 }
25 }
26
27 CMyString::~CMyString( void )
28 {
29 if ( this->m_pData)
30 {
31 delete[] this->m_pData;
32 this->m_pData = 0;
33 }
34 }
35
36 CMyString& CMyString::operator=( const CMyString& str)
37 {
38 if ( this != &str )
39 {
40 delete[] this->m_pData;
41 if ( !str.m_pData )
42 {
43 this->m_pData = 0;
44 }
45 else
46 {
47 this->m_pData = new char[ strlen( str.m_pData ) + 1 ];
48 strcpy( this->m_pData, str.m_pData );
49 }
50 }
51 return *this;
52 }
53
54 CMyString CMyString::operator+( const CMyString& str )
55 {
56 CMyString newString;
57 if ( !str.m_pData )
58 {
59 newString = *this;
60 }
61 else if ( !this->m_pData )
62 {
63 newString = str;
64 }
65 else
66 {
67 newString.m_pData = new char[ strlen( this->m_pData ) + strlen( str.m_pData ) + 1 ];
68 strcpy( newString.m_pData, this->m_pData );
69 strcat( newString.m_pData, str.m_pData );
70 }
71
72 return newString;
73
74 }
75
76 bool CMyString::operator==( const CMyString& str )
77 {
78 if ( strlen(this->m_pData) != strlen( str.m_pData ) )
79 {
80 return false;
81 }
82 else
83 {
84 return strcmp( this->m_pData, str.m_pData ) ? false : true;
85 }
86 }
87
88 char CMyString::operator[]( int idx)
89 {
90 if ( idx > 0 && idx < strlen( this->m_pData ) )
91 return this->m_pData[idx];
92 }
93
94 int CMyString::getLength()
95 {
96 return strlen(this->m_pData);
97 }
98
99 std::ostream& operator<<( std::ostream& os, const CMyString& str )
100 {
101 os<< str.m_pData;
102 return os;
103 }
string类实现（C++）
时间： 2024-12-21 00:03:12