第四章课堂作业

来源：互联网发布：磁力链接解析源码编辑：程序博客网时间：2024/06/08 18:07
#include<istream>  using namespace std;  #include<string.h>    class String  {    public:        String();        virtual ~String();        String(int n);        String(const String &s2);        String(const char *str);        String & operator = (const String &s1);        friend bool operator >(String &string1, String &string2);        friend bool operator <(String &string1, String &string2);        friend bool operator == (String &string1, String &string2);        friend bool operator <= (String &string1, String &string2);        friend bool operator >= (String &string1, String &string2);        friend ostream& operator << (ostream& , String &);            private:        char *s;    };    String::String()//初始化，默认长度为100  {      s = new char[100];        s[0] = '\0';  }    String::String(int n)//构造一个大小为n的数组  {      s = new char [n];        s[0] = '\0';  }    String::~String()//析构  {      if(s)      {          delete s;      }      s = NULL;  }    String::String(const String &s2)//拷贝构造函数  {      this->s = new char [strlen[s2.s]+1]  ;  //ERROR :C:\Users\Administrator\Desktop\I  can  do  it\fsada.cpp(69) : error C2107: illegal index, indirection not allowed                                        //ERROR: C:\Users\Administrator\Desktop\I  can  do  it\fsad//error //C2440: 'initializing' : //cannot convert from 'char *' to 'int'            s[0] = '\0';        strcpy(s, s2.s);  }    String::String(const char *str)  {      s = new char[strlen[str]+1];//同上 = =。        s[0] = '\0';  }    String& String :: operator = (const String &s1)//赋值构造函数  {      if(this == &s1)       {          return *this;      }      else      {          delete   []s1; //ERROR :No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called                         //ERRORE:fatal error C1903: unable to recover from previous error(s); stopping compilation                                         s1 = new char [strlen[s1.s]+1];            return *this;      }    }    bool operator > (String &string1, String &string2)  {      if(strcmp(string1.s , string2.s) > 0)                     return true;        else            return false;  }    bool operator < (String &string1, String &string2)  {      if(strcmp(string1.s , string2.s) < 0)                     return true;        else            return false;  }    bool operator == (String &string1, String &string2)  {      if(strcmp(string1.s , string2.s) == 0)                     return true;        else            return false;  }    bool operator <= (String &string1, String &string2)  {      if(strcmp(string1.s , string2.s) > 0)                     return false;        else            return true;  }    bool operator >= (String &string1, String &string2)  {      if(strcmp(string1.s , string2.s) < 0)                     return false;        else            return true;  }    ostream& operator << (ostream& output , String & s3)  {        output << s3.s << endl;        return output;    }
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