MyString

//string.h

#include<iostream>

using std::ostream;

using std::istream;

#ifndef STRING1_H_

#define STRING1_H_

class String{

private:

    char *str;

    int len;

    static int num_strings;

    static const int CINLIM = 80;

public:

    String(const char *s);

    String();

    String(const String &st);

    ~String();

    int length() const { return len;}

    //overloading

    String & operator=(const String & str);

    String & operator=(const char *s);

    char & operator[](int i);

    const char & operator[](int i) const;

    //overloading friend

    friend bool operator<(const String& st1, const String & st2);

    friend bool operator>(const String& st1, const String & st2);

    friend bool operator==(const String & st1, const String & st2);

    friend ostream & operator<<(ostream & os, const String & st);

    friend istream & operator>>(istream & is, String & st);

    //static func

    static int HowMany();

};

#endif

//string.cxx

#include<iostream>

#include "string1.h"

using std::cout;

using std::cin;

int String::num_strings = 0;

int String::HowMany()

{

    return num_strings;

}

String::String(const char *s)

{

    len = std::strlen(s);

    str = new char[len+1];

    std::strncpy(str, s, len);

    str[len] = 0;

    num_strings++;

}

String::String()

{

    len = 0;

    str = new char[1];

    str[0] = 0;

    num_strings++;

}

String::String(const String &st)

{

    len = st.len;

    str = new char[len+1];

    std::strcpy(str,st.str);

    num_strings++;

}

String::~String()

{

    --num_strings;

    delete [] str;

}

String & String::operator=(const String & str)

{

    if(this == &str)

        return *this;

    delete [] this->str;

    len = str.len;

    this->str = new char[len+1];

    std::strcpy(this->str, str.str);

    return *this;

}

String & String::operator=(const char *s)

{

    delete[] str;

    len = std::strlen(s);

    str = new char[len+1];

    std::strcpy(str, s);

    return *this;

}

char & String::operator[](int i)

{

    return str[i];

}

const char & String::operator[](int i) const

{

    return str[i];

}

bool operator<(const String  & st1, const String & st2)

{

    return (std::strcmp(st1.str, st2.str) < 0);

}

bool operator>(const String & st1, const String & st2)

{

    return (std::strcmp(st1.str, st2.str) > 0);

}

bool operator==(const String & st1, const String & st2)

{

    return (std::strcmp(st1.str, st2.str) == 0);

}

ostream & operator<<(ostream & os, const String & st)

{

    os << st.str;

    return os;

}

istream & operator>>(istream & is, String & st)

{

    char temp[String::CINLIM];

    is.get(temp, String::CINLIM);

    if(is)

        st = temp;

    while(is && is.get() != '\n');

    return is;

}