因為用長整數寫，太大的階乘會出錯，所以用陣列寫。(最少要到30階) 其中的陣列方式大概如以下的兩數相乘程式。 各位大大能幫忙試試嗎??    // Multiplication, 整數乘法 A * B = C import java.io.*; public class mul {    public static void main(String args[]) throws IOException    {          int numA[]=new int[3];       int numB[]=new int[3];       int numC[]=new int[6];       int M[]=new int[4];       int num1,num2;       String str1,str2;           BufferedReader buf;              buf=new BufferedReader(new InputStreamReader(System.in));              System.out.print("Input first number:");       str1=buf.readLine();               num1=Integer.parseInt(str1);               System.out.print("Input second number:");       str2=buf.readLine();               num2=Integer.parseInt(str2);              int numtmp=10;       for (int i=0; i<3; i ) { numA[i]=num1%numtmp; numB[i]=num2%numtmp; num1=num1/numtmp; num2=num2/numtmp; } System.out.println("The integer A is " numA[2] numA[1] numA[0]); System.out.println("The integer B is " numB[2] numB[1] numB[0]); // Multiplication, A[] * B[] = C[] for (int i=0; i<6; i ) numC[i]=0; int tag,multemp,addtemp,tagm; for (int i=0; i<3; i ) { tag=0; for (int j=0; j<3; j ) { multemp=numA[j]*numB[i] tag; M[j]=multemp%numtmp; tag = multemp/numtmp; } M[3]=tag; System.out.println("M is " M[3] M[2] M[1] M[0]); tagm=0; for (int j=0; j<4; j ) { addtemp=numC[i j] M[j] tagm; numC[i j]=addtemp%numtmp; tagm=addtemp/numtmp; } numC[i 3]=numC[i 3] tagm; } System.out.println("The A * B is " numC[5] numC[4] numC[3] numC[2] numC[1] numC[0]); } }