[C + +] Operator overloading for string string classes

In C + + there is a newly defined type string that can be used without the hassle of manipulating strings, and some advanced operator overloads make her easier to use

The following is the definition of the string class and the definition of the member function:

#ifndef operator_operator_h#define operator_operator_h#include<iostream> #include <string.h>using    namespace Std;class string{friend ostream& operator<< (ostream &out, const String &s);        Friend istream& operator>> (IStream &in, String &s);p ublic:string (const char *STR = NULL) {            if (str = = NULL) {m_data = new char[1];        M_data[0] = ' + ';            } else {m_data = new Char[strlen (str) +1];        strcpy (M_DATA,STR);        }} String (const string &s) {m_data = new Char[strlen (s.m_data) +1];    strcpy (M_data,s.m_data);            } string& operator= (const String &s) {if (This! = &s) {free (m_data);            m_data = new Char[strlen (s.m_data) +1];        strcpy (M_data,s.m_data);    } return *this;    } ~string () {delete []m_data; } friend ostream& operator<< (Ostream &Out, const String &s) {out<<s.m_data;    return out;        } friend istream& operator>> (IStream &in, String &s) {in>>s.m_data;    return in; } string operator+ (const string &s); s = s1 + s2 string operator+= (const string &s);    S1 + = S2 char& operator[] (int index);    BOOL operator== (String &s);    BOOL Operator!= (String &s);   BOOL Operator> (String &s);    S1 > S2 bool operator<= (String &s);    BOOL operator< (String &s); BOOL Operator>= (String &s);p Rivate:char *m_data;};    String string::operator+= (const string &s)//s1 + = s2{m_data = new Char[sizeof (m_data) +1];    strcat (M_data,s.m_data); return *this;}    String string::operator+ (const string &s)//s = S1 + s2{strcat (m_data, s.m_data); return *this;}    BOOL string::operator== (String &s) {if (strcmp (m_data, S.m_data) ==0) return true; return false;} BOOL String::operator!= (String &s) {if (strcmp (m_data,s.m_data)!=0) return true; return false;}    BOOL String::operator> (String &s)//s1 > s2{if (strcmp (m_data,s.m_data) >0) return true; return false;}    BOOL String::operator<= (String &s) {if (strcmp (m_data,s.m_data) >=0) return true; return false;}    BOOL string::operator< (String &s) {if (strcmp (m_data,s.m_data) <0) return true; return false;}    BOOL String::operator>= (String &s) {if (strcmp (m_data,s.m_data) <=0) return true; return false;}    char& string::operator[] (int index) {//char*p= m_data;//return * (P+index); return M_data[index];} #endif

The following is the test program:

#include "operator.h" int main () {    String s ("s");    String S1 ("s");    String S2;    String S3;    s2 = s+s1;    S+=S1;    cout<< "s+=s1=" <<s<<endl;    cout<< "s[2] =" <<s[0]<<endl;//    if (s = = S1)//        cout<<1<<endl;//    if (s! = S1 )//        cout<<0<<endl;//    if (S > S1)//        cout<< "S>S1" <<endl;//    if (s >= s1)//        cout<< "S>=S1" <<endl;//    if (S < S1)//        cout<< "S<S1" << endl;//    if (s <=s1)//        cout<< "s<=s1" <<endl;    cin>>s3;    cout<< "s3=" <<s3<<endl;//please test    return 0 separately;}

Enter S3 and don't know why it's capitalized.

[C + +] Operator overloading for string string classes