Êëàññ - "ìîÿ ñòðîêà" st

#include<stdio.h>

#include <stdlib.h>

#include <string.h>

class st

{ private:

   int l;           // äëèíà

   char * s;        // àäðåñ ñòðîêè

  public:

   st();            // êîíñòðóêòîð áåç ïàðàìåòðà

   st(char *);    // êîíñòðóêòîð ñ èíèöèàëèçèðóþùèì ïàðàìåòðîì

   ~st();

const char * put(const char *); // âçÿòü óêàçàòåëü íà

                                                ñòðîêó

const char * get();               // çàïèñàòü ñòðîêó

 st(const st & x);                // êîíñòðóêòîð

                                         êîïèðîâàíèÿ

 st & operator=(const st & x);    // îïåðàòîð

                                       ïðèñâàèâàíèÿ

 st & operator+=(const st & x);  //óíàðíûé îïåðàòîð +=

 friend

 st operator+(const st & x, const st & y);

                            // äðóæåñòâåííàÿ ôóíêöèÿ +

 friend

 st operator-(const st & x, const st & y);

                            // äðóæåñòâåííàÿ ôóíêöèÿ -

 void ch(char); // äëÿ òåñòà - èçìåíèòü 0-é ñèìâîë

 void pr( char *); // äëÿ òåñòà - ðàñïå÷àòàòü....

};

void st::ch(char x)

 { if (s[0] != '\0') this->s[0]=x;

   return;

 };

 void st::pr(char tit[]="")

{printf("%s[%d]<%s>\n",tit,l,s);return; };

st::st()

{ l=1; s=new char[1]; s[0]='\0';}; 

st::st(char * d)

{ l=strlen(d)+1; s=new char[l];

  strcpy(s, d);

  }; 

st::~st()

{

   delete [] s;

   l=0;

};

 st & st::operator=(const st & x)

 {

   if( this == &x ) return *this;

   delete [] this->s;

   this->l=x.l;

   this->s=new char[l];

   strcpy(s, x.s);

   return *this;

 };

 // ÊÎÑÒÐÓÊÒÎÐ ÊÎÏÈÐÎÂÀÍÈß !!!!!!!!!!!!!!!!!!!!!!!!

 //   ïîïðîáóéòå óáðàòü.....

 st::st(const st & x)

 {

   this->l=x.l;

   this->s=new char[l];

   strcpy(s, x.s);

 };

 // óíàðíûé +=

 st & st::operator+=(const st & x)

 {

   char *p;    int lp=this->l+x.l-1;

   p=new char[lp];

   sprintf(p,"%s%s",this->s, x.s);

   // â ð - êîíàêòåíèòðîâàííàÿ ñòðîêà

   delete [] this->s;

   this->l=lp;

   this->s=new char[lp];

   strcpy(this->s, p);

   return *this;

 };

 // áèíàðíûé +

 st operator+(const st & x, const st & y )

 {

   char *p;

   st temp;//! âûçûâàåòñÿ êîíñòðóêòîð êîïèðîâàíèÿ

   int lp=x.l + y.l -1;

   p=new char[lp];

   sprintf(p,"%s%s", x.s, y.s);

   // â ð - êîíàêòåíèòðîâàííàÿ ñòðîêà

   temp.l=lp;

   temp.s=new char[lp];

   strcpy(temp.s, p);

   return temp;

 };

 // áèíàðíûé -

 st operator-(const st & x, const st & y )

 {

   printf("x=%s  y=%s \n", x.s, y.s);

   char *p;

   st temp;  // !!!!!!!!!!!!!!!!!!!!!

   int i,j;   

   int k;

   char tchar;

   int flag;

   int n=x.l+1;

   p=new char[n];

   k=0;

   for(i=0; i< x.l; i++)

    {   tchar=x.s[i];

        // åñòü ëè tchar â y.s ?

        flag=0;

        for(j=0;j<y.l;j++) 

          if(tchar==y.s[j]) {flag=1; break;};

        if(flag==0) p[k++]=tchar;

    };

    p[k]='\0';

   // â ð - íîâàÿ ñòðîêà

   temp.l=k;

   temp.s=new char[k];

   strcpy(temp.s, p);

   return temp;

 };

const char * st::put(const char * d)

{

  delete [] s;

  l=strlen(d)+1; s=new char[l];

  strcpy(s, d);

  return s;

};

const char * st::get()

{

  return s;

}

int main(int argc, char *argv[] )

{ st a1, a2, a3, a4="êóêó";

  const char * p;

  p=a1.put("ïðèâåò"); 

  printf("***p===<%s>\n",p);

  a1.pr("a1= ....  ==> ");

  a2=a1;

  a2.pr("a2=a1 => ");

  a3.put("Âñåì "); a3.pr("a3.put(...) ==> ");

  a3+=a2;        a3.pr("a3+=a2 ==> ");

  printf("*************************\n");

  a1.ch('$');      a1.pr("a1($) ==> ");

  a2=a1;

  a2.ch('@');    a2.pr("a1(@) ==> ");

  a4.pr("a4 ==> ");

  printf("*************************\n");

  a2=a1 + " +++ " + a4;    a2.pr("a1 +++ a4 ==> ");

  a1 = "ïîáåäà!";   a1.pr("a1=.... ==> ");

  a2 = a1 - "ïî";   a2.pr("a2=a1 - ïî ==> ");

  a3 = a1 - "àï";   a3.pr("a3=a1 - àï ==> ");

  return 0;

}

===========================================================

C:\Test\cpp\b_str>t

***p===<ïðèâåò>

a1= ....  ==> [7]<ïðèâåò>

a2=a1 => [7]<ïðèâåò>

a3.put(...) ==> [6]<Âñåì >

a3+=a2 ==> [12]<Âñåì ïðèâåò>

*************************

a1($) ==> [7]<$ðèâåò>

a1(@) ==> [7]<@ðèâåò>

a4 ==> [5]<êóêó>

*************************

a1 +++ a4 ==> [16]<$ðèâåò +++ êóêó>

a1=.... ==> [8]<ïîáåäà!>

x=ïîáåäà!  y=ïî

a2=a1 - ïî ==> [5]<áåäà!>

x=ïîáåäà!  y=àï

a3=a1 - àï ==> [5]<îáåä!>

C:\Test\cpp\b_str>