C++大数运算

来源：互联网发布：华3交换机端口激活命令编辑：程序博客网时间：2024/05/20 20:57
    #include<cstdio>      #include<iostream>      using namespace std;      const int maxn = 200;      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 = (int num) {          char s[maxn];          sprintf(s, "%d", num);          *this = s;          return *this;        }        bign operator = (const char* num) {          len = strlen(num);          for(int i = 0; i < len; i++) s[i] = num[len-i-1] - '0';          return *this;        }        string str() const {          string res = "";          for(int i = 0; i < len; i++) res = (char)(s[i] + '0') + res;          if(res == "") res = "0";          return res;        }        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;        }        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-1; i++){            c.s[i+1] += c.s[i] / 10;            c.s[i] %= 10;          }          c.clean();          return c;        }        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;        }        bool operator < (const bign& b) const{          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) const{          return b < *this;        }        bool operator <= (const bign& b) {          return !(b > *this);        }        bool operator == (const bign& b) {          return !(b < *this) && !(*this < b);        }        bign operator += (const bign& b) {          *this = *this + b;          return *this;        }      };      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 >> b;        a += b;        cout << a << endl;        return 0;      }
0 0