string.cpp

//Venix Cador
//String ADT
//Cs 23001
#include "string.h"

String::String(const int cap){

  size = cap;
  s= new char[size];
  s[0] = 0;
  length = 0;
}

String::String(const char c, const int cap){

  size = cap;
  s = new char[size];
  s[0] = c;
  s[1] = 0;
  length = 1;//because the length is one
}
//copy constructor

String::String(const String& rhs, const int cap)
{
  //check if capacity is shorter than length
  if(cap <= rhs.length){
    size = rhs.length + 1;
  }else{
    size = cap;
  }
  s = new char[size];


  //copy chars to string
  for(length = 0; rhs.s[length] != 0;  ++length){
    s[length] = rhs.s[length];
  }
  s[length] = 0;
}
String::String(const char str[], const int cap){

  //calculate the length of the string
  for (length = 0; str[length] != 0; ++length){}

  //resize the size is needed
  if(length > cap - 1) {
       size = length + 1;
     }else {
       size = cap;
     }
     s = new char[size];

   //copy chars to string
     for(int index = 0; str[index] != 0; ++index){
       s[index] = str[index];
  }

  s[length] = 0;
}


//destructor for string
String::~String()
{
  length = 0;
  delete [] s;
}

//finds the first occurance of a char in a string with zero offset
//Ex: str.finchar('d');
int String::findchar(char find) const
{
  for(int i = 0; i < length; ++i){
    if(s[i] == find){
      return i;
    }
  }
  return -1;
}

//finds how many times a string occurs in another string
//Ex: str.findstr(find);

int String::findstr(const String& find) const
{
  int result = 0;
  if( length > find.length){
    for(int index = 0, findindex = 0; index < length; ++index, findindex = 0){
      while ( s[index + findindex] == find.s[findindex] && findindex <= find.length){
	++findindex;
	if (findindex == find.length) {
	  ++result;
	  index += findindex;
	}
      }
    }
  }
  return result;
}
bool String::operator==(const String& rhs) const {

  if(length != rhs.length) return false;

       for(int i = 0; i < length; ++i){
           if(s[i] != rhs.s[i]) return false;

  }
  return true;
}
/*
 *Returns the character from a specified index. Returns null if it is out of bounds.
*Ex: char d = str[1];
*/

char String::operator [] (int index) const{

  if( index >= length || index < 0) {
    std::exit(0);
  }
  return s[index];
}
char& String::operator [] (int index){

  if(index >= length || index < 0){
    std:: exit(0);
  }
  return s[index];
}

String String::operator + (const String& rhs) const {

  int index = 0;

  String result;

  result.length = length + rhs.length;

  // Taking the index and goes to the string in order to find the length of the first string
  for(; index <length; ++index)
    {
	    result.s[index] = s[index];
    }

  for(int rhsindex = 0; rhsindex < rhs.length; ++rhsindex, ++index)
    {
      result.s[index] = rhs.s[rhsindex];
    }
     result.s[index] = 0;

     return result;
}
//greater than operator this is fliped compare to the less than operator
bool String::operator < (const String& rhs) const
{
  int i = 0;
  while((s[i] != 0) && (rhs.s[i] != 0) && (i< MaxString)) {

    if (s[i] < rhs.s[i]) return true;
    if(s[i] == rhs.s[i]) ++i;
    else return false;
  }

  if(rhs.s[i] != 0)
    return false;

  return true;

}

// the output function
std::ostream& operator <<(std::ostream& out, const String& rhs){
  int i = 0;
  while(rhs[i] != 0){
    out<< rhs[i];
    ++i;
  }
  return out;
}
//The input function
std::istream& operator >>(std::istream& in, String& rhs){
  char tmp;

  while (in) {
    in.get(tmp);

    if (!in.eof()) {
      rhs += tmp;
    }
  }

  return in;
}
//the substr function

String String::substr(int left, int right) const
{

  String result;

  if (right <= 0 || right > length){
    right = length;

  }

 for(int i = left; i < right; ++i){
   result  = result + s[i];
 }

 result.length = right - left;
 result[right] = 0;

  return result;
}
//Swaps two strings
//Ex: str1.swap(str2);

//reallocate string's capacity to a specified value
//Ex: str.reallpcate(50);

void String::reallocate(const int cap)
{
  String temp(*this, cap);
  swap(temp);
}
//swap two strings
//Ex: str1.swap(str2)
void String::swap(String& str)
{

  char *temp = s;
  s = str.s;
  str.s = temp;

  int temp_cap = size;
  size = str.size;
  str.size = temp_cap;

  int temp_length = length;
  length = str.length;
  str.length = temp_length;
}
//assignment operator for string
//Ex: String str = rhs_str;
String& String::operator = (String rhs)
{

  swap(rhs);
  return *this;
}