java版 100!

 

class BigNum 
...{
    public static void main(String[] args) 
    ...{
        JieCheng j=new JieCheng();
        j.doJieCheng(300);
        j.output();
    }
}
class JieCheng
...{
    private StringBuffer result;//结果
    private StringBuffer tem;//加数
    public JieCheng()
    ...{
        tem=new StringBuffer();
        result=new StringBuffer();
    }
    public void doJieCheng(int n)
    ...{
        if(n>=1)
        ...{
            tem.append('1');
            result.append('1');
        }
        for(int i=2;i<=n;i++)
        ...{

            for(int j=1;j<=i-1;j++)//*****只要相加i-1次就可以得到了，而不是i次
            ...{
                int t=0;//进位
                int r=0;//余数
                for(int k=0;k<result.length();k++)
                ...{
            
                    int sum=result.charAt(k)-'0';
                    if(k<tem.length())
                    ...{
                        sum=sum+(tem.charAt(k)-'0');
                    }
                    sum+=t;
                    t=sum/10;
                    r=sum%10;
                    char temChar='0';
                    temChar+=r;
                    result.setCharAt(k,temChar);
                    //System.out.println("r="+r);
                }
                if(t!=0)
                ...{

                    result.append(t+"");
                }
            }
            tem=new StringBuffer();
            for(int k=0;k<result.length();k++)
            ...{
                tem.append(result.charAt(k));
            }
        }
    }
    public void output()
    ...{
        for(int i=result.length()-1;i>=0;i--)
        ...{
            System.out.print(result.charAt(i));
        }
    }
};