# include <iostream>
# include <memory>
# include <cstring>
using namespace std;
class MyString {
private:
char *m_data;
public:
MyString();
MyString(const char* ptr);
MyString(const MyString& rhs);
~MyString();
MyString& operator=(const MyString& rhs);
MyString operator+(const MyString& rhs);
char operator[](const unsigned int index);
bool operator==(const MyString& rhs);
friend ostream& operator<<(ostream& output, const MyString &rhs);
};
//默认的构造函数
MyString::MyString() {
m_data = new char[];
*m_data = '\0';
}
//使用const char* 来初始化
MyString::MyString(const char* ptr) {
if (NULL == ptr) {
m_data = new char[];
*m_data = '\0';
} else {
int len = strlen(ptr);
m_data = new char[len + ];
strcpy(m_data, ptr);
}
}
//拷贝构造函数
MyString::MyString(const MyString& rhs) {
int len = strlen(rhs.m_data);
m_data = new char[len + ];
strcpy(m_data, rhs.m_data);
}
bool MyString::operator ==(const MyString& rhs) {
int result = strcmp(m_data, rhs.m_data);
if ( == result)
return true;
else
return false;
}
//赋值操作符
MyString& MyString::operator =(const MyString& rhs) {
if (this != &rhs) {
delete[] m_data;
m_data = new char[strlen(rhs.m_data) + ];
strcpy(m_data, rhs.m_data);
}
return *this;
}
//重载运算符+
MyString MyString::operator+(const MyString &rhs) {
MyString newString;
if (!rhs.m_data)
newString = *this;
else if (!m_data)
newString = rhs;
else {
newString.m_data = new char[strlen(m_data) + strlen(rhs.m_data) + ];
strcpy(newString.m_data, m_data);
strcat(newString.m_data, rhs.m_data);
}
return newString;
}
//重载下标运算符
char MyString::operator [](const unsigned int index) {
return m_data[index];
}
//析构函数
MyString::~MyString() {
delete[] m_data;
}
//重载<<
ostream& operator<<(ostream& output, const MyString &rhs) {
output << rhs.m_data;
return output;
}
int main() {
const char* p = "hello,world";
MyString s0 = "hello,world";
MyString s1(p);
MyString s2 = s1;
MyString s3;
s3 = s1;
MyString s4 = s3 + s1;
bool flag(s1 == s2);
cout << s0 << endl;
cout << s1 << endl;
cout << s2 << endl;
cout << s3 << endl;
cout << flag << endl;
char result = s3[];
cout << result << endl;
cout << s4 << endl;
return ;
}