String类成员方法实现

//实现String类的成员方法

class String

{

public:

    String( const char* str =NULL ) // 普通构造

       ~String();  //析构

    String( const String& other); //拷贝构造函数

    String& operater=(const String& other ) //赋值运算重载

private:

    char* m_data;

}

 

String::String(const char* str )

{

    if ( str == NULL )

    {

       m_data = new char[1];

       m_data = '\0';

    }

    else

    {

       m_data = new char[ strlen(str) + 1 ];

       strcpy( m_data,str );

    }

}

 

String::String(const String &other)

{

    m_data = new char[ strlen(other.m_data) +1 ];

    strcpy( m_data,other.m_data);

}

 

String&String::operater=(constString&other )

{

    if ( this == &other )

    {

       return *this;//自赋值

    }

    delete []m_data;

    m_data = new char[ strlen(other.m_data )+ 1 ];

    strcpy( m_data,other.m_data);

    return *this;

}

 

String::~String()

{

    delete []m_data;

}