Big Integer Class using Dynamic Arrays

[bodyguard814]

I have become overwhelmed an frustrated at these current operator overloads!

Currently I still can not get my +,* or istream operators working at all!

I could sincerely use some help!

#include <iostream>
#include <cstring>
#include "myint.h"


using namespace std;

MyInt::MyInt(int n)		
// default int constructor
{
	digits = NULL;		// setting array to null
	if(n <= 0)
	{
		setDefault();		
	}
	else
		Int2Array(n);
}

MyInt::~MyInt()		
// destructor
{
	delete[] digits;
}

MyInt::MyInt(const char *cstrg)		
// default cstring constructor 
{
	digits = NULL;
	Cstrg2Array(cstrg);
}

MyInt::MyInt(const MyInt & d)		
// copy constructor 
{
	maxSize = d.maxSize;
	currentSize = d.currentSize;

	digits = new int[d.maxSize];

	for(int i = 0; i < currentSize; i++)
		digits[i] = d.digits[i];
}


void MyInt::Int2Array(int n)
{
	currentSize = 0;	// intializing 
	maxSize = 2;
	int x = n;

		while(x != 0)	// finding length of the number
		{
			x = x / 10;		
			currentSize++;
		}
		maxSize = maxSize + currentSize;	// increasing array size to have 2 extra storage spaces then the number
	
	
	digits = new int[maxSize];		// creating new int array to pointer

	x = n;
	for(int i = 0; i < currentSize; x /=10, i++)	// for loop to assign each array location with a integer 
	{
		digits[i] = (x % 10);		// Mods the least significant digit and places it in the current array slot
	}
}

void MyInt::Cstrg2Array(const char *cstrg)
{
	currentSize = strlen(cstrg);	// reading number of char
	maxSize = currentSize + 2;

	digits = new int[maxSize];

	const char* read = cstrg;	// temp variable 
	for(int i = currentSize -1; i >= '\0'; i--)		// for loop to convert then assign each character to the array of int
	{
		int temp = C2I(*read);

		if(temp == -1)
		{
			setDefault();
			return;
		}
		digits[i] = temp;	// assigning array elements 

		read++;
	}
}


void MyInt::setDefault()	// sets default paramaters with error checking
{
	if(digits != NULL )		// deletes previous array if one was created
	{
		delete[] digits;
	}
	currentSize = 1;
	maxSize = 3;
	digits = new int[maxSize];
	digits[0] = 0;
}

void MyInt::testfunc()
{
	cout<< currentSize << endl;
	cout<< maxSize << endl;
	
	for(int i = 0; i < currentSize; i++)
	{
		cout<< digits[i]<< endl;
	}
}

// Operator overloads

//Member Functions

MyInt& MyInt::operator= (const MyInt & d)
// assigment operator
{
	if(this != &d)	// only makes a copy if variable isnt equal already
	{
		delete[] digits;

	maxSize = d.maxSize;
	currentSize = d.currentSize;

	digits = new int[d.maxSize];

	for(int i = 0; i < currentSize; i++)
		digits[i] = d.digits[i];

	}
	return *this;
}

MyInt& MyInt::operator++()
{
	int i = 0;

	while(digits[i] == 9)
	{
		digits[i] = 0;
		if(i == currentSize -1)
		{
			digits[currentSize] = 1;
			currentSize++;
			maxSize++;
		
			return *this;
		}
		i++;
		
	}
	digits[i]++;
	return *this;


}

MyInt MyInt::operator++(int) 
{
	MyInt temp = *this;
	int i = 0;

	while(digits[i] == 9)
	{
		digits[i] = 0;
		if(i == currentSize -1)
		{
			digits[currentSize] = 1;
			currentSize++;
			maxSize++;
		
			return temp;
		}
		i++;
		
	}
	digits[i]++;
	return temp;

}

MyInt& MyInt::operator--()
{
	int i = 0;

	while(digits[i] == 0)
	{
		digits[i] = 9;
		if(i == currentSize -1)
		{
			digits[i]--;
			return *this;
		}
		i++;
		
	}
	if(digits[i] == 1)
			{
				currentSize--;
				maxSize--;
				return *this;
			}
	digits[i]--;
	return *this;
}

MyInt MyInt::operator--(int)
{
	MyInt temp = *this;
	int i = 0;

	while(digits[i] == 0)
	{
		digits[i] = 9;
		if(i == currentSize -1)
		{
			digits[i]--;
			return temp;
		}
		i++;
		
	}
	if(digits[i] == 1)
			{
				currentSize--;
				maxSize--;
				return temp;
			}
	digits[i]--;
	return temp;
}
// Friend Functions

istream& operator>>(istream& , MyInt& )
{

}


ostream& operator<< (ostream &os, const MyInt &c)
{
	for(int i = c.currentSize -1 ; i >= 0; i--)
	{
		os << c.digits[i];
	}
	
	return os;

}

MyInt operator* (const MyInt& x, const MyInt& y)
{

}

MyInt operator+ (const MyInt& x, const MyInt& y)
{
	MyInt Temp;
	if( x.currentSize > y.currentSize)
	{
		int carry = 0;
		for(int i = x.currentSize -1; i >=0 ; i--)
		{
			int j;
			
			j = ( x.digits[i] + y.digits[i] + carry);
			Temp.digits[i] = (j % 10);
			carry = (j / 10);
			Temp.currentSize++;
			Temp.maxSize++;
		}
	}
	else 
	{
		int carry = 0;
		for(int i = y.currentSize -1; i >=0 ; i--)
		{
			int j;
			
			j = ( x.digits[i] + y.digits[i] + carry);
			Temp.digits[i] = (j % 10);
			carry = (j / 10);
			Temp.currentSize++;
			Temp.maxSize++;
		}
	}

	return Temp;
	
}

bool operator< (const MyInt& x, const MyInt& y)
{
}
bool operator> (const MyInt& x, const MyInt& y)
{
}
bool operator<= (const MyInt& x, const MyInt& y)
{}
bool operator>= (const MyInt& x, const MyInt& y)
{}
bool operator== (const MyInt& x, const MyInt& y)
{}
bool operator!= (const MyInt& x, const MyInt& y)
{}

int MyInt::C2I(char c)
// converts character into integer (returns -1 for error)
{
   if (c < '0' || c > '9')	return -1;	// error
   return (c - '0');				// success
}

char MyInt::I2C(int x)
// converts single digit integer into character (returns '\0' for error)
{
   if (x < 0 || x > 9)		return '\0';	// error
   return (static_cast<char>(x) + '0'); 	// success
}


// Add in operator overload and member function definitions 

[KyiannaJones]

Example:

int main()
{
  int size;

  std::cin >> size;

  int *array = new int[size];

  delete [] array;

  return 0;
}

I'm not exactly sure what you are asking, but here's a link that has an example of Dynamic Arrays:

http://stackoverflow.com/questions/4029870/how-to-create-a-dynamic-array-of-integers

***Don't forget to delete and allocate new data