C + + String additions and deletions check and change

#include  <iostream>using namespace std; #include  <assert.h>class string{ Public: string (char*str= "")  {  _size = strlen (str);   _capacity =  _size + 1;  _str = new char[_capacity];  strcpy (_str,  STR);  } ~string ()  {  if  (_STR)   {   delete[]_str;    _size = 0;   _capacity = 0;   _str =  Null;  } } void pushback (char ch)  {  checkcapacity (_size+2);   _str[_size] = ch;  _str[++_size] =  '; } void  ' Popback ()  {  assert (_size > 0);   --_size;  _str[_size] =   '  }//insert single character  void insert (Size_t pos, char ch)  {  assert ( Pos <= _size);   checkcapacity (_size+2);  size_t index = _size;  while  ( Index >= pos)   {   _str[Index + 1] = _str[Index];    --index;  }  _str[pos] = ch;  _size++; }//inserting a string  void insert (SIZE_T&NBSP;POS,&NBSP;CHAR*STR)  {  assert (pos <= _size);   size_t index = _size;  int length = strlen (str);   checkcapacity (_size+1+length);  while  (index >= pos)   {    _str[index + length] = _str[index];   --index;  }     for  (int i = 0; i < length; ++i)    {   _str[pos + i] = str[i];  }  _size +=  length; }//find a single character  size_T find_ch (char ch)  {  size_t length = strlen (_STR);   for   (int i = 0; i < length; i++)   {   if   (_str[i] == ch)    {    return i;   }   }  return -1; }//Find sub-string  size_t find_str (const char*sub)  {   size_t srcsize = _size;  size_t subsize = strlen (sub);   size_t SrcIndex = 0;      while  (srcindex  <=_size-subsize)       {   size_t SubIndex = 0;    size_t begin = SrcIndex;   while  (begin <  Srcsize    &&subindex < subsize    &&_str [Begin] == sub[subindex])    {    begin++;    subindex++;   }    if  (subindex == subsize)    {    return  srcindex;   }   srcindex++;  }  return -1; }   void erase (Size_t pos)  {  assert (POS);  for  (int i  = pos; i < _size-1; ++i)   {   _str[i] = _ str[i + 1];  }  _size--;  _str[_size] =  '; }  string &operator+= ( const string& s)  {  this->insert (_size, &NBSP;S._STR);   return *this; } char*cstr ()  {  return _str;  }private: void checkcapacity (int needsize)  {  if  (needsize >=  _capacity)   {   _capacity = needsize>2 * _capacity ? needsize:2*_capacity;   _str =  (char*) realloc (_str, _capacity);   }  }private: char*_str; int _size; int _capacity;};

This article is from the "printf Return Values" blog, so be sure to keep this source http://10741125.blog.51cto.com/10731125/1754464

C + + String additions and deletions check and change