#include<iostream>

using namespace std;

class CString
{
    char * m_pbuff; //指向字符串的指针
    int m_length; //表示当前字符串的最大允许长度，也就是字符数组的长度
public:
    CString(); //构造函数1，设置为空字符串，m_length=100
    CString(char *src); //构造函数2，在考虑了src的长度后初始化当前对象，m_length >= src的长度 + 1
    CString(char ch); //构造函数3，0号元素赋值为ch, m_length=100
    CString(CString & a);
    int SetString(char *src); //设置字符串，在考虑了src的长度后设置当前对象, m_length >= src的长度 + 1
    friend ostream& operator<<(ostream& Out, const CString& S);  //输出字符串
    ~CString()
    {
        delete []m_pbuff;
    }
};
CString::CString()
{
    m_length = 100;
    m_pbuff = new char[m_length];
    for (int i = 0; i < m_length; ++i)
        m_pbuff[i] = '\0';
   
}
CString::CString(char *src)
{
    m_length = strlen(src) + 1;
    m_pbuff = new char[m_length];
    int i;
    for (i = 0; i < m_length; ++i)
        m_pbuff[i] = src[i];
    m_pbuff[i] = '\0';
}
CString::CString(char ch)
{
    m_length = 100;
    m_pbuff = new char[m_length];
    m_pbuff[0] = ch;
    m_pbuff[1] = '\0';
}
int CString::SetString(char *src)
{
    m_length = strlen(src) + 1;
    m_pbuff = new char[m_length];
    int i;
    for (i = 0; i < m_length; ++i)
        m_pbuff[i] = src[i];
    m_pbuff[i] = '\0';
    return 1;
}
ostream& operator<<(ostream& Out, const CString& S)
{
    Out << S.m_pbuff << endl;
    return Out;
}
CString::CString(CString & a)
{
    m_length = a.m_length;
    m_pbuff = new char[a.m_length];
    int i;
    for (i = 0; i < m_length; ++i)
        m_pbuff[i] = a.m_pbuff[i];
    m_pbuff[i] = a.m_pbuff[i];
}

void main()
{
    CString s1;
    cout << s1;
    s1.SetString("abc1");
    cout << s1;
    CString s2("abc2");
    cout << s2;
    CString s3('a');
    cout << s3;
    CString s4(s2);
    cout << s4;
}

多谢版主，新手上路，刚开始学C++，没太注意，版主有什么好的书籍推荐吗?不怕难的!