//trừ
SoLon Tru(SoLon b)
{
if (b.ToString() == "0")
{
return(this);
}
else if (ToString() == "0")
{
return(b);
}
var max = Math.Max(arr.Length, b.arr.Length);
if (arr.Length < max)
{
arr = MakeSameLength(arr, max);
}
if (b.arr.Length < max)
{
b.arr = MakeSameLength(b.arr, max);
}
var nho = 0;
var ret = new int[max];
for (int i = max - 1; i >= 0; i--)
{
var hieu = arr[i] - b.arr[i];
if (nho == 1)
{
hieu -= 1;
nho = 0;
}
if (hieu < 0)
{
hieu += 10;
nho = 1;
}
ret[i] = hieu;
}
if (nho != 0)
{
ret[0] = ret[0] - nho;
}
return(new SoLon(ret));
}
//cộng
SoLon Cong(SoLon b)
{
if (ToString() == "0")
{
return(b);
}
if (b.ToString() == "0")
{
return(this);
}
var max = Math.Max(this.arr.Length, b.arr.Length);
if (this.arr.Length < max)
{
this.arr = MakeSameLength(arr, max);
}
if (b.arr.Length < max)
{
b.arr = MakeSameLength(b.arr, max);
}
var ret = new int[max + 1];
int nho = 0;
for (int i = max - 1; i >= 0; i--)
{
var tong = arr[i] + b.arr[i];
if (nho != 0)
{
tong++;
nho = 0;
}
if (tong > 9)
{
nho = 1;
tong -= 10;
}
ret[i + 1] = tong;
}
if (nho != 0)
{
ret[0] = nho;
}
return(new SoLon(ret));
}
