public NumberString Add(NumberString anotherNumber)
{
char[] x, y;
if (this.number.Length > anotherNumber.Number.Length)
{
x = this.number.ToCharArray();
y = anotherNumber.Number.ToCharArray();
}
else
{
y = this.number.ToCharArray();
x = anotherNumber.Number.ToCharArray();
}
char[] sum = new char[x.Length];
int carry = 0;
for (int iterX = x.Length - 1, iterY = y.Length - 1; iterX >= 0; iterX--, iterY--)
{
if (x[iterX] < 48 || x[iterX] > 57)
{
throw new Exception("The input number is not in number format! Please enter valid digits from 0 - 9");
}
if (iterY >= 0 && (y[iterY] > 57 || y[iterY] < 48))
{
throw new Exception("The input number is not in number format! Please enter valid digits from 0 - 9");
}
int miniSum = x[iterX] + carry - 48; // Removing Ascii
if (iterY >= 0)
{
miniSum += y[iterY] - 48; // Removing Ascii
}
carry = miniSum / 10;
sum[iterX] = Convert.ToChar((miniSum % 10) + 48);
}
if (carry > 0)
{
return(new NumberString(carry.ToString() + new string(sum)));
}
else
{
return(new NumberString(sum));
}
}
public NumberString Multiply(NumberString anotherNumber)
{
NumberString product = null, a = null, b = null, c = null, d = null;
try
{
string x, y = anotherNumber.Number;
short negativeCount = 0;
if (this.IsNegative())
{
x = this.number.Substring(1);
negativeCount++;
}
else
{
x = this.number;
}
if (anotherNumber.IsNegative())
{
y = anotherNumber.Number.Substring(1);
negativeCount++;
}
else
{
y = anotherNumber.Number;
}
if (x.Equals(ZERO) || y.Equals(ZERO))
{
return(new NumberString(ZERO));
}
if (x.Length == 1 && y.Length == 1)
{
int miniProduct = Convert.ToInt32(x) * Convert.ToInt32(y);
if (negativeCount % 2 == 1)
{
return(new NumberString("-" + miniProduct));
}
return(new NumberString(miniProduct));
}
bool applyEfficiency = false;
if (x.Length == y.Length && this.isTwoMultiple(x.Length))
{
applyEfficiency = true;
}
int xFirstHalfLength = x.Length / 2;
int xSecondHalfLength = (x.Length + 1) / 2;
int yFirstHalfLength = y.Length / 2;
int ySecondHalfLength = (y.Length + 1) / 2;
a = new NumberString(x.Substring(0, xFirstHalfLength), false);
b = new NumberString(x.Substring(xFirstHalfLength), false);
c = new NumberString(y.Substring(0, yFirstHalfLength), false);
d = new NumberString(y.Substring(yFirstHalfLength), false);
NumberString firstProduct = a.Multiply(c);
NumberString acProduct = firstProduct.Clone();
firstProduct.PadRight(xSecondHalfLength + ySecondHalfLength, '0');
NumberString fourthProduct = b.Multiply(d);
if (applyEfficiency)
{
NumberString secondProduct = a.Add(b).Multiply(c.Add(d));
secondProduct = secondProduct.Subtract(acProduct).Subtract(fourthProduct);
secondProduct.PadRight(xSecondHalfLength, '0');
product = firstProduct.Add(secondProduct).Add(fourthProduct);
}
else
{
NumberString secondProduct = a.Multiply(d);
secondProduct.PadRight(xSecondHalfLength, '0');
NumberString thirdProduct = b.Multiply(c);
thirdProduct.PadRight(ySecondHalfLength, '0');
product = firstProduct.Add(secondProduct).Add(thirdProduct).Add(fourthProduct);
}
if (negativeCount % 2 == 1)
{
return(new NumberString("-" + product.Number));
}
}
catch (Exception ex)
{
Console.WriteLine(a.number);
Console.WriteLine(b.number);
Console.WriteLine(c.number);
Console.WriteLine(d.number);
throw ex;
}
return(product);
}
public NumberString Subtract(NumberString anotherNumber)
{
char[] x, y;
bool swap = true;
if (this.number.Length > anotherNumber.Number.Length)
{
swap = false;
}
if (this.number.Length == anotherNumber.Number.Length)
{
for (int iter = 0; iter < this.number.Length; iter++)
{
if (this.number[iter] > anotherNumber.Number[iter])
{
swap = false;
break;
}
}
}
x = swap ? anotherNumber.Number.ToCharArray() : this.number.ToCharArray();
y = swap ? this.number.ToCharArray() : anotherNumber.Number.ToCharArray();
char[] difference = new char[x.Length];
int borrow = 0;
bool stillBorrow = false;
for (int iterX = x.Length - 1, iterY = y.Length - 1; iterX >= 0; iterX--, iterY--)
{
if (x[iterX] < 48 || x[iterX] > 57)
{
throw new Exception("The input number is not in number format! Please enter valid digits from 0 - 9");
}
if (iterY >= 0 && (y[iterY] > 57 || y[iterY] < 48))
{
throw new Exception("The input number is not in number format! Please enter valid digits from 0 - 9");
}
int firstDigit, secondDigit;
if (x[iterX] == 48 && borrow > 0)
{
firstDigit = 9; // Assiging 9 directly in case of borrow
stillBorrow = true;
}
else
{
firstDigit = x[iterX] - borrow - 48; // Removing Ascii
borrow = 0;
}
int miniDifference = firstDigit;
if (iterY >= 0)
{
secondDigit = y[iterY] - 48;
if (firstDigit >= secondDigit)
{
miniDifference -= secondDigit;
borrow = stillBorrow ? borrow : 0;
}
else
{
miniDifference = miniDifference + 10 - secondDigit;
borrow = 1;
}
}
difference[iterX] = Convert.ToChar(miniDifference + 48);
}
string finalDiff = new string(difference);
if (finalDiff.Equals("0"))
{
return(new NumberString(finalDiff));
}
int indexOfNumber = finalDiff.IndexOfAny(NUMBERS);
if (indexOfNumber == -1 && finalDiff[finalDiff.Length - 1] == '0') // To handle the situations like "0" or "000" etc.
{
return(new NumberString("0"));
}
finalDiff = finalDiff.Substring(indexOfNumber);
if (swap)
{
return(new NumberString("-" + finalDiff));
}
else
{
return(new NumberString(finalDiff));
}
}