Programmer Power Tools/Programmer Power Tools.iso/microcrn/issue_40.arc/DAIMS.ARC/STRINGS.CPP

C/C++ Source or Header | 1988-02-10 | 3.8 KB | 236 lines

#include <stdio.h>
#include "strings.hxx"
#undef TEST
/*
-*++ string::string(): un-initialized string object
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

 string::string()
{
  p = new srep;
  p->s = 0;
  p->n = 1;
}

/*
-*++ string::string(): build a string object from a string of characters
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

 string::string(char* s)
{
  p = new srep;
  p->s = new char[strlen(s)+1];
  strcpy(p->s,s);
  p->n = 1;
}


/*
-*++ string::string(): build a string object from a string reference
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

 string::string(string& x)
{
  x.p->n++;
  p = x.p;
}


/*
-*++ string::~string(): destructor for string objects
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

 string::~string()
{
  if (--p->n == 0){
    delete p->s;
    delete p;
  }
}


/*
-*++ string::operator=(): string object assignment to character string
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

string & string::operator=(char * s)
{
  if (p->n > 1) {
    p->n--;
    p = new srep;
  }
  else if (p->n == 1)
    delete p->s;

  p->s = new char[strlen(s) + 1 ];
  strcpy(p->s,s);
  p->n = 1;
  return *this;
}


/*
-*++ string::operator=(): string object assignment to string object
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

string& string::operator=(string& x)
{
  x.p->n++;
  if (--p->n == 0) {
    delete p->s;
    delete p;
  }
  p = x.p;
  return *this;
}



/*
-*++ string::operator<<(): stream output of a string
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

ostream& operator<<(ostream& s, string& x)
{
  return s << x.p->s << " [" << x.p->n << "]\n";
}


/*
-*++ string::operator>>(): stream input to a string
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

istream & operator>>(istream& s, string& x)
{
  char buf[256];
  s >> buf;
  x = buf;
  cout << "echo: " << x << "\n";
  return s;
}


/*
-*++ string::operator[](): index into a string
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

char & string::operator[](int i)
{
  if (i<0 || strlen(p->s) < i) error("index out of range");
  return p->s[i];
}


/*
-*++ string::operator+(): add two string objects
**
** (*++ history:
**      7 Dec 87    Bruce Eckel    Creation date
** ++*)
**
** (*++ detailed:
** ++*)
*/

string& operator+(string& x, string& y)
{
  char buf[256];
  strcpy(buf,x.p->s);
  strcat(buf,y.p->s);
  string & tmp =  *new string(buf);
  return tmp;
}

#ifdef TEST
main()
{
  string x = "this is string x";
  string y = "this is string y";
  cout << x << y << "\n";
  cout << x + y << "\n";
  string z = "this is string z ";
  string q = "this is string q ";
  cout << z + q << "\n" << q + x << "\n";



/*  string x[100];
  int n;

  cout << "here we go\n";
  for (n = 0; cin >> x[n]; n++) {
    string y;
    if (n == 100) error("too many strings");
    cout << (y = x[n]);
    if (y == "done") break;
  }
  cout << "here we go back again\n";
  for (int i=n-1; 0 <= i; i--) cout << x[i];
*/
}

#endif TEST  /* use test for testing string class, undef otherwise */