//--------------------------------------------------------------------
//
//  Laboratory 3                                          stradt.cpp
//
//  SOLUTION: Array implementation of the String ADT
//
//--------------------------------------------------------------------

#include <iostream.h>
#include <iomanip.h>
#include <assert.h>
#include <string.h>
#include "stradt.h"

//--------------------------------------------------------------------

stradt:: stradt ( int numChars )

// Creates an empty string. Allocates enough memory for numChars+1
// characters (defaults to 1 character).

  : bufferSize(numChars+1)

{
    buffer = new char [ bufferSize ];   // Allocate memory for buffer
    assert ( buffer != 0 );             // Confirm allocation
    buffer[0] = '\0';                   // Set string to empty
}

//--------------------------------------------------------------------

stradt:: stradt ( const char *charSeq )

// Creates a string containing the delimited sequence of characters
// charSeq. Allocates enough memory for this string.

{
    bufferSize = strlen(charSeq) + 1;   // Account for null

    buffer = new char [ bufferSize ];   // Allocate memory
    assert ( buffer != 0 );

    strcpy(buffer,charSeq);             // Copy the string
}

//--------------------------------------------------------------------

stradt:: ~stradt ()

// Frees the memory used by a string.

{
    delete [] buffer;
}

//--------------------------------------------------------------------

int stradt:: length () const

// Returns the number of characters in a string (excluding the
// null character).

{
    return strlen(buffer);
}

//--------------------------------------------------------------------

char stradt:: operator [] ( int n ) const

// Returns the nth character in a string -- where the characters are
// numbered beginning with zero.

{
    if ( n >= 0  &&  n <= length() )
       return buffer[n];
    else
       return '\0';
}

//--------------------------------------------------------------------

void stradt:: operator = ( const stradt &rightString )

// Assigns rightString to a string.

{
    int rlen = rightString.length();   // Length of rightString

    if ( rlen >= bufferSize )          // If rightString will not fit
    {
       delete [] buffer;                    // Release buffer and
       bufferSize = rlen + 1;               //  allocate a new
       buffer = new char [ bufferSize ];    //  (larger) buffer
       assert ( buffer != 0 );
    }

    strcpy(buffer,rightString.buffer);   // Copy rightString
}

//--------------------------------------------------------------------

void stradt:: clear ()

// Clears a string -- i.e., makes it empty. The buffer size
// remains unchanged.

{
    buffer[0] ='\0';
}

//--------------------------------------------------------------------

void stradt:: showStructure () const

// Outputs the characters in a string. This operation is intended for
// testing/debugging purposes only.

{
    int j;   // Loop counter

    for ( j = 0 ; j < bufferSize ; j++ )
        cout << j << "\t";
    cout << endl;
    for ( j = 0 ; buffer[j] != '\0' ; j++ )
        cout << buffer[j] << "\t";
    cout << "\\0" << endl;
}