C#版 大數計算機–乘法

class BigMultiply:BigCalculate
 

   {
       
public override string Oper(string num1, string num2)
       
{
           
if (num1.Equals("0")||num2.Equals("0"))
           
{
               
return "0";
           
}

           
List liAllNum = new List();//儲存乘數每位乘法的結果
           
List liCh = new List();//儲存乘數每位乘法中每一位的結果

           
//將長度較長的數字賦給num1，方便後面計算
           
if (num1.Length < num2.Length)
           
{
               
ChangeNum(ref num1, ref num2);
           
}
 
           
int flag;
           
for (int i = num2.Length-1; i >=0; i--)
           
{
               
//初始化上一位乘法中的資料
               
liCh.Clear();
               
flag = 0;
               
//計算第i位乘以第j位
               
for (int j = num1.Length - 1; j >= 0; j--)
               
{
                   
liCh.Add((char)((num2[i] - '0') * (num1[j] - '0')+flag+'0'));
                   
flag = (liCh[liCh.Count-1] -'0')/ 10;
                   
liCh[liCh.Count - 1] = (char)((liCh[liCh.Count - 1] - '0') %
10+'0');
               
}
               
//若進位不為0，則在加進位
               
if (flag>0)
               
{
                   
liCh.Add((char)(flag+'0'));
               
}
               
//添加結果集
               
liAllNum.Add(InvertOrder(new string(liCh.ToArray()))+new
string('0',liAllNum.Count));
           
}
           
int count = 0;
           
string res="0";
           
//調用add方法，將每一位乘法所得的結果相加，即為結果
           
BigAdd addOper= new BigAdd();
           
while (count
           
{
               
res = addOper.Oper(res,liAllNum[count]);
               
count++;
           
}

           
return res;  
       
}
}