Help with this C++ code, String Class implementation. DO NOT USE/INCLUDE string

Question

Help with this C++ code,

String Class implementation. DO NOT USE/INCLUDE string type (e.g. #include <string>)

Objective: Learning design and use of object oriented programming, operator overloading, constructors (copy constructor, default constructor etc.), destructors, ‘this’ pointer, friendship relation, and static variables.

Input: String or strings (e.g. s1+s2 will return concatenation of strings s1 and s2)

Output: Required operations’ outputs e.g. s1>s2 returns true or false, s1[2] returns third char in string s1, s1.Length() returns length of s1 etc.

Project Description: You are required to create your own String class (Note: String class is different than built in string class) like string type in C++. This class should include following operations:

Separate specifications from implementation. Keep header file and class implementation in separate files.

Can initialize created object with a given string or given instance of the same class (use copy constructor)

Dynamically allocates memory for a given string (e.g. String s(“Joe”); in this case allocates 3 memory spaces for String class instance s)

Returns string length if it is requested (e.g. s.Length())

Clears dynamically allocated memory for String object while destructing (do it in destructor)

Checks boundaries (e.g. if String s size is 10, s[11]= ‘A’; will display error message on screen)

In public section of the String class only include interfaces. All other variables and functions must be in private section.

Overloads + operator so that two string can be concatenated. (e.g. String s1,s2,s3; s3 = s1+s2; ) when only have s1+s2; concatenated string will be included in s1.

Overloads [ ] operator so that s[index] will be possible.

Compares two given objects (e.g. String a,b) a>b or a<b or a==b. To do that overload <,>,== operators

Copies one object to another (e.g. a=b or a=b=c) (overload ‘=’ operator for this purpose)

When required returns number of objects created so far. (e.g. String obj; obj.count()). Obj.count() returns total number of non-empty String objects).

Can get input from the istream class instance (e.g. cin>>s;). Make it friend of the String class.

Can output to the ostream class instance (e.g. cout<<s;). Make it friend of the String class. Total:

You may use below given class definition as a reference. Complete code for IntArray class is given under Sample Codes folder in Blackboard.

class IntArray

{ private:

   int *aptr;                     // Pointer to the array    int arraySize;                 // Holds the array size    void subscriptError();         // Handles invalid subscripts public:

   IntArray(int);                 // Constructor

   IntArray(const IntArray &);    // Copy constructor

   ~IntArray();                   // Destructor

   int size() const               // Returns the array size       { return arraySize; }

    int &operator[](const int &); // Overloaded [] operator    friend ostream& operator <<(ostream& stream,IntArray ob); };

Explanation / Answer

main.cpp

// This program demonstrates the IntArray class's bounds-checking ability.
#include <iostream>
#include "IntArray.h"
using namespace std;

int main()
{
   const int SIZE = 10; // Array size

   // Define an IntArray with 10 elements.
   IntArray table(SIZE);

   // Store values in the array.
   for (int x = 0; x < SIZE; x++)
      table[x] = x;

   // Display the values in the array.
   for (x = 0; x < SIZE; x++)
      cout << table[x] << " ";
   cout << endl;

   // Attempt to use an invalid subscript...
   cout << "Now attempting to use an invalid subscript. ";
   table[SIZE + 1] = 0;
   return 0;
}

IntArray.cpp

// Implementation file for the IntArray class
#include <iostream>
#include <cstdlib>   // For the exit function
#include "IntArray.h"
using namespace std;

//*******************************************************
// Constructor for IntArray class. Sets the size of the *
// array and allocates memory for it.                   *
//*******************************************************

IntArray::IntArray(int s)
{
   arraySize = s;
   aptr = new int [s];
   for (int count = 0; count < arraySize; count++)
      *(aptr + count) = 0;
}

//******************************************************
// Copy Constructor for IntArray class.                *
//******************************************************

IntArray::IntArray(const IntArray &obj)
{
   arraySize = obj.arraySize;
   aptr = new int [arraySize];
   for(int count = 0; count < arraySize; count++)
      *(aptr + count) = *(obj.aptr + count);
}

//******************************************************
// Destructor for IntArray class.                      *
//******************************************************

IntArray::~IntArray()
{
   if (arraySize > 0)
      delete [] aptr;
}

//***********************************************************
// subscriptError function. Displays an error message and   *
// terminates the program when a subscript is out of range. *
//***********************************************************

void IntArray::subscriptError()
{
   cout << "ERROR: Subscript out of range. ";
   exit(0);
}

//*******************************************************
// Overloaded [] operator. The argument is a subscript. *
// This function returns a reference to the element     *
// in the array indexed by the subscript.               *
//*******************************************************

int &IntArray::operator[](const int &sub)
{
   if (sub < 0 || sub >= arraySize)
      subscriptError();
   return aptr[sub];
}

IntArray.h

// Specification file for the IntArray class
#ifndef INTARRAY_H
#define INTARRAY_H

class IntArray
{
private:
   int *aptr;                     // Pointer to the array
   int arraySize;                 // Holds the array size
   void subscriptError();         // Handles invalid subscripts
public:
   IntArray(int);                 // Constructor
   IntArray(const IntArray &);    // Copy constructor
   ~IntArray();                   // Destructor

   int size() const               // Returns the array size
      { return arraySize; }

   int &operator[](const int &); // Overloaded [] operator
};
#endif

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.