I have a problem I am trying to create a MyInt class to hanlde very
large ints. Its for a class, therefore I can only do what the teach
tells me. I want to be able to overload the insertion operator so that
I can read in one digit at a time from the buffer and if the digit is 0
- 9 then put it into the dynamic array which stores each digit of this
large int.
#include <iostream>
#include <string>
#include "myint.h"
using namespace std;
int C2I(char c)
// converts character into integer (returns -1 for error)
{
if (c < '0' || c > '9') return -1; // error
return (c - '0'); // success
}
char 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
}
MyInt::MyInt(int n)
// default constructor for the MyInt class which takes an int as its
param
{
int i;
int temp = n; //temp var used because n should not be changed yet
int div;
curSize = 0;
while(temp/=10) curSize++; //calculate the length of n
curSize++;
maxSize = curSize + 5;
bigInt = new int[maxSize];
for(i = 0; i < maxSize; i++)
//initialize the array to all 0's
bigInt[i] = -1;
if(n < 0)
Reset();
else
{
for(i = curSize - 1; i >= 0; i--)
//places each digit into a slot in the array
{
if(curSize >= maxSize)
Resize();
div = 10;
bigInt[i] = (n % div);
n/=10;
}
}
}
MyInt::MyInt(char* s)
// constructor for the MyInt class which takes a literal
{
int i;
curSize = 0;
maxSize = curSize + 5;
bigInt = new int[maxSize];
for(i = 0; i < maxSize; i++)
//initialize the array to all 0's
bigInt[i] = -1;
if(s == NULL)
Reset();
else
{
for(i = 0; i < strlen(s); i++)
//converts each char to a digit then palces it into the array
{
if(curSize >= maxSize)
Resize();
if(C2I(s[i]) != -1)
{
bigInt[i] = C2I(s[i]);
curSize++;
}
else
{
Reset();
break;
}
}
}
}
MyInt::~MyInt()
// deltes all dynamically allocated memory to prevent memory leaks
{
delete [] bigInt;
}
MyInt::MyInt(const MyInt & m)
// copy constructor used to copy all member data
{
curSize = m.curSize;
maxSize = m.maxSize;
bigInt = new int[m.maxSize];
for(int i = 0; i < curSize; i++)
bigInt[i] = m.bigInt[i];
}
MyInt& MyInt::operator= (const MyInt & m)
// assignment operator
{
if(this != &m)
{
delete [] bigInt;
curSize = m.curSize;
maxSize = m.maxSize;
bigInt = new int[m.maxSize];
for(int i = 0; i < curSize; i++)
bigInt[i] = m.bigInt[i];
}
return *this;
}
void MyInt::Reset()
// resets the array to 0
{
curSize = 1;
maxSize = 1;
delete [] bigInt;
bigInt = new int[1];
bigInt[0] = 0;
}
void MyInt::Resize()
{
cout << "resizing arr...";
int * temp = new int[maxSize+=5];
for(int i = 0; i < curSize; i++)
temp[i] = bigInt[i];
delete [] bigInt;
bigInt = temp;
}
MyInt operator+ (const MyInt& x, const MyInt& y)
{
//not done
return 0;
}
MyInt operator* (const MyInt& x, const MyInt& y)
{
//not done
return 0;
}
bool operator< (const MyInt& x, const MyInt& y)
{
if(x.curSize < y.curSize)
return true;
else if(x.curSize > y.curSize)
return false;
else
{
for(int i = 0; i < x.curSize; i++)
{
if(x.bigInt[i] > y.bigInt[i])
return false;
else if(x.bigInt[i] < y.bigInt[i])
return true;
}
}
return false;
//returns false because if it reaches this part then all the numbers
are the same
//therefore x is not less than y they are equal
}
bool operator> (const MyInt& x, const MyInt& y)
{
if(x < y)
return false;
else if(x.curSize > y.curSize)
return true;
else
{
for(int i = 0; i < x.curSize; i++)
{
if(x.bigInt[i] > y.bigInt[i])
return true;
else if(x.bigInt[i] < y.bigInt[i])
return false;
}
}
return true;
}
bool operator>= (const MyInt& x, const MyInt& y)
{
if(x > y || x == y)
return true;
return false;
}
bool operator<= (const MyInt& x, const MyInt& y)
{
if(x < y || x ==y)
return true;
return false;
}
bool operator!= (const MyInt& x, const MyInt& y)
{
if(x == y)
return false;
return true;
}
bool operator== (const MyInt& x, const MyInt& y)
{
if(x > y)
return false;
else if(x < y)
return false;
else
return true;
}
istream& operator >> (istream &s, MyInt& y)
{
int c;
s.ignore();
return s;
}
ostream& operator << (ostream &s, const MyInt& y){
for(int i = 0; i < y.curSize; i++)
s << y.bigInt[i];
return s;
}
