public Integer Swap(Integer other)
{
int s = sign;
this.magnitude.Swap(other.magnitude);
this.sign = other.sign;
other.sign = s;
return this;
}
public Integer Clone()
{
Integer n = new Integer(magnitude.Clone());
n.sign = this.sign;
return n;
}
public Integer SetValue(Integer newVal)
{
this.magnitude.SetValue(newVal.magnitude);
this.sign = newVal.sign;
return this;
}
/// <summary>
/// Returns the smallest positive remainder of the Euclidian divison of x by y.
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <returns></returns>
public static Integer Remainder(Integer x, Integer y)
{
if (y.sign == 0)
throw new DivideByZeroException();
Natural.Modulus(x.magnitude, y.magnitude); // Return smalles positive remainder
x.sign = 1;
return x;
}
public static Integer Subtract(Integer x, Integer y)
{
y.sign = -y.sign;
Integer.Add(x, y);
y.sign = -y.sign;
return x; // x - y = x + (-y)
}
public static Integer Multiply(Integer x, Integer y)
{
Natural.Multiply(x.magnitude, y.magnitude);
x.sign *= y.sign;
return x;
}
public static Integer Negate(Integer x)
{
x.sign *= -1;
return x;
}
/// <summary>
/// Returns the smallest (closest to zero) positive or negative remainder of the Euclidian division of x by y.
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <returns></returns>
public static Integer Modulus(Integer x, Integer y)
{
if (y.sign == 0)
throw new DivideByZeroException();
Integer pos = Integer.Remainder(x, y);
Integer neg = pos - y;
if (neg.magnitude < pos.magnitude)
return x.SetValue(neg); // Set x to neg and return
else
return pos; // x is already pos
}
public static Integer Increment(Integer n)
{
return Integer.Add(n, 1);
}
public static Integer Divide(Integer x, Integer y)
{
if (y.sign == 0)
throw new DivideByZeroException();
Natural.Divide(x.magnitude, y.magnitude);
x.sign /= y.sign;
return x;
}
public static Integer Decrement(Integer n)
{
return Integer.Subtract(n, 1);
}
public static Integer Add(Integer x, Integer y)
{
if (y.sign == 0)
return x;
else if (x.sign == 0)
{
x.sign = y.sign;
x.magnitude = y.magnitude.Clone();
return x; // Always update x instead of just returning y
}
else if (x.sign == y.sign)
{
x.magnitude += y.magnitude;
return x;
}
else
{
// 5 + (-2) = 5 - (+2) = +3
// 5 + (-7) = 5 - (+7) = -2
// -5 + 2 = -3
// -5 + 7 = +2
if (x.magnitude > y.magnitude)
{
Natural.Subtract(x.magnitude, y.magnitude);
return x;
}
else if (x.magnitude < y.magnitude)
{
x.sign = -x.sign;
x.magnitude = y.magnitude - x.magnitude; // Can't use in-place subtract here, would create a reference to y's magnitude
return x;
}
else
{
x.sign = 0;
x.magnitude = Natural.Zero;
return x;
}
}
}
