c/c++语言开发共享c++大数模板

  //支持正数的运算。两数相减也要为正数   #include  #include  using namespace std;  const int maxn=10000;  struct bign    {        int len, s[maxn];        bign ()        {            memset(s, 0, sizeof(s));            len = 1;        }        bign (int num) { *this = num; }        bign (const char *num) { *this = num; }        bign operator = (const int num)        {            char s[maxn];            sprintf(s, "%d", num);            *this = s;            return *this;        }        bign operator = (const char *num)        {            for(int i = 0; num[i] == '0'; num++) ;  //去前导0            len = strlen(num);            for(int i = 0; i < len; i++) s[i] = num[len-i-1] - '0';            return *this;        }        bign operator + (const bign &b) const //+        {            bign c;            c.len = 0;            for(int i = 0, g = 0; g || i < max(len, b.len); i++)            {                int x = g;                if(i < len) x += s[i];                if(i < b.len) x += b.s[i];                c.s[c.len++] = x % 10;                g = x / 10;            }            return c;        }        bign operator += (const bign &b)        {            *this = *this + b;            return *this;        }        void clean()        {            while(len > 1 && !s[len-1]) len--;        }        bign operator * (const bign &b) //*        {            bign c;            c.len = len + b.len;            for(int i = 0; i < len; i++)            {                for(int j = 0; j < b.len; j++)                {                  c.s[i+j] += s[i] * b.s[j];                }            }          for(int i = 0; i < c.len; i++)            {              c.s[i+1] += c.s[i]/10;                c.s[i] %= 10;            }          c.clean();          return c;      }      bign operator *= (const bign &b)        {          *this = *this * b;            return *this;        }      bign operator - (const bign &b)        {            bign c;            c.len = 0;            for(int i = 0, g = 0; i < len; i++)            {              int x = s[i] - g;              if(i < b.len) x -= b.s[i];              if(x >= 0) g = 0;              else                {                    g = 1;                    x += 10;                }                c.s[c.len++] = x;            }            c.clean();            return c;        }        bign operator -= (const bign &b)        {            *this = *this - b;            return *this;        }        bign operator / (const bign &b)        {            bign c, f = 0;            for(int i = len-1; i >= 0; i--)            {                f = f*10;                f.s[0] = s[i];                while(f >= b)                {                    f -= b;                    c.s[i]++;                }            }            c.len = len;            c.clean();            return c;        }        bign operator /= (const bign &b)        {            *this  = *this / b;            return *this;        }        bign operator % (const bign &b)        {            bign r = *this / b;            r = *this - r*b;            return r;        }        bign operator %= (const bign &b)        {            *this = *this % b;            return *this;        }        bool operator < (const bign &b)        {            if(len != b.len) return len < b.len;            for(int i = len-1; i >= 0; i--)            {                if(s[i] != b.s[i]) return s[i] < b.s[i];            }            return false;        }        bool operator > (const bign &b)        {            if(len != b.len) return len > b.len;            for(int i = len-1; i >= 0; i--)            {                if(s[i] != b.s[i]) return s[i] > b.s[i];            }            return false;        }        bool operator == (const bign &b)        {            return !(*this > b) && !(*this < b);        }        bool operator != (const bign &b)        {            return !(*this == b);        }        bool operator <= (const bign &b)        {            return *this < b || *this == b;        }        bool operator >= (const bign &b)        {            return *this > b || *this == b;        }        string str() const        {            string res = "";            for(int i = 0; i < len; i++) res = char(s[i]+'0') + res;            return res;        }  };    istream& operator >> (istream &in, bign &x)    {        string s;        in >> s;        x = s.c_str();        return in;    }        ostream& operator << (ostream &out, const bign &x)    {        out << x.str();        return out;    }  int main(){  	bign a,b;  	cin>>a;  	cout<