Self-Made Strings

string.cpp

#include "string.h"

String::String()
{
    m_characters = new char[0];
    m_size = 0;
}

String::String( const int size )
{
    m_size = size;
    m_characters = new char[size];
}

String::String( const char* str )
{
    m_size = 0;
    int i = 0;
    while ( str[i] )
    {
        m_size++;
        i++;
    }
    m_characters = new char[m_size];
    for (int i = 0; i < m_size; i++)
        m_characters[i] = str[i];
}

String::String( const String& string )
{
    m_size = string.m_size;
    m_characters = new char[m_size];
    for ( int i = 0; i < m_size; i++ ) 
        m_characters[i] = string.m_characters[i];
}

String::~String()
{
    delete [] m_characters;
}

char& String::operator []( int index )
{
    return m_characters[index];
}

const char String::operator []( int index ) const
{
    return m_characters[index];
}

String& String::operator=( const String& string )
{
    if ( this != &string )
    {
        m_size = string.m_size;
        m_characters = new char[m_size];
        for (int i = 0; i < m_size; i++ )
            m_characters[i] = string.m_characters[i];
    }
    return *this;
}

void String::Print( std::ostream& os ) const
{
    for ( int i = 0; i < m_size; i++ )
        os << m_characters[i];
    os << "\n";
}

int String::GetSize() const 
{
    return m_size;
}

char ToUpper( char ch )
{
    if ( islower( ch ) )
        return ch - static_cast<char>( 32 );
    else
        return ch;
}

bool operator > ( const String& lstr, const String& rstr )
{
    int size = std::min( lstr.GetSize(), rstr.GetSize() );
    for ( int i = 0; i < size; i++ )
    {
        if ( ToUpper( lstr[i] ) > ToUpper( rstr[i] ) )
            return true;
        else if ( ToUpper( lstr[i] ) < ToUpper( rstr[i] ) )
            return false;
    }
    return lstr.GetSize() > rstr.GetSize();
}

bool operator >= ( const String& lstr, const String& rstr )
{
    int size = std::min( lstr.GetSize(), rstr.GetSize() );
    for ( int i = 0; i < size; i++ )
    {
        if ( ToUpper( lstr[i] ) >= ToUpper( rstr[i] ) )
            return true;
        else if ( ToUpper( lstr[i] ) < ToUpper( rstr[i] ) )
            return false;
    }
    return lstr.GetSize() >= rstr.GetSize();
}

bool operator < ( const String& lstr, const String& rstr )
{
    int size = std::min( lstr.GetSize(), rstr.GetSize() );
    for ( int i = 0; i < size; i++ )
    {
        if ( ToUpper( lstr[i] ) < ToUpper( rstr[i] ) )
            return true;
        else if ( ToUpper( lstr[i] ) > ToUpper( rstr[i] ) )
            return false;
    }
    return lstr.GetSize() < rstr.GetSize();
}

bool operator <= ( const String& lstr, const String& rstr )
{
    int size = std::min( lstr.GetSize(), rstr.GetSize() );
    for ( int i = 0; i < size; i++ )
    {
        if ( ToUpper( lstr[i] ) <= ToUpper( rstr[i] ) )
            return true;
        else if ( ToUpper( lstr[i] ) > ToUpper( rstr[i] ) )
            return false;
    }
    return lstr.GetSize() <= rstr.GetSize();
}

string.h

#ifndef __STRING_H_
#define __STRING_H_

#include <algorithm>
#include <ctype.h>
#include <iostream>

#include "heap.h"

namespace tg 
{

class String 
{
public:
    String();
    String( const int size );
    String( const char* str );
    String( const String& string );
    ~String();

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

    String& operator=( const String& string ); 

    void Print( std::ostream& os ) const;
    int GetSize() const;
private:
    char *m_characters;
    int m_size;
};

char ToUpper( char letter );
bool operator > ( const String& lstr, const String& rlsr );
bool operator >= ( const String& lstr, const String& rlsr );
bool operator < ( const String& lstr, const String& rlsr );
bool operator <= ( const String& lstr, const String& rlsr );


#endif // __STRING_H_