大数类

短命女 2022-08-25 08:42 191阅读 0赞

大数类

#include <iostream>
    #include <cstdio>
    #include <cstring> 
    
    using namespace std;
    
    const int maxn = 1000;
    
    struct Bign{
    	
    	int len;  //有效长度 
    	int s[maxn]; //存放大数
    	
    	//构造函数 ，变量初始化 
    	Bign(){ memset(s,0,sizeof(s));len = 1;} 
    	
    	//重载赋值操作，可以直接用 x = "123456789034" 的方式来为x赋值  
    	//将字符串逆序存储在 int s[]内 
    	Bign operator = (const char * num){
    		len = strlen(num);
    		for(int i=0;i<len; i++) s[i] = num[len-i-1] - '0';
    		return *this;
    	}
    	
    	Bign operator = (int num){
    		char s[maxn];
    		sprintf(s, "%d", num);
    		*this = s;
    		return *this;
    	}
    	
    	Bign(int num){ *this = num; }
    	Bign(const char* num){ *this = num; }
    	
    	string toString() const{
    		string str = "";
    		for(int i=len-1; i>=0; i--) str += (char)(s[i]+'0');
    		return str;
    	}
    	
    	Bign operator + (const Bign &b ) const {
    		Bign c; c.len = 0;
    		int i,carry,maxl = max(len,b.len);
    		for( i =carry =0; i<maxl; i++){
    			int tmp = s[i] + b.s[i] + carry;
    			c.s[c.len++] = tmp % 10;
    			carry = tmp / 10;
    		}
    		while(i<len)  c.s[c.len++] += s[i++];  
    		while(i<b.len)  c.s[c.len++] += b.s[i++]; 
    		return c;
    	} 
    	
    	//去除数组中多余的0 
    	void clear() {
    		while(len>1 && !s[len-1])len--; 
    	} 
    	
    	Bign operator * (const Bign &b) const {
    		Bign c; c.len = len + b.len;
    		//对于a的每一位 用 b的每一位去成一遍 
    		for(int i=0; i<len; i++) 
    			for(int j=0; j<b.len; j++)
    				c.s[i+j] += s[i] * b.s[j];
    		//处理进位 
    		for(int i=0; i<c.len-1; i++){
    			c.s[i+1] += c.s[i] / 10;
    			c.s[i] %= 10;
    		}
    		//去除多余0，更正c.len 
    		c.clear();
    		return c;		
    	}
    	
    	friend istream &operator >> (istream &in, Bign &n) {
    		string s;
    		in >> s;
    		n = s.c_str();
    		return in;
    	} 
    	
    	friend ostream &operator << (ostream &out, const Bign &n) {
    		out << n.toString();
    		return out;
    	}
    		
    };
    
    
    int main ()
    {
    	
    	Bign n1;
    	n1 = "23784589493050034059009342324324";
    	cout << " n1 = " << n1 << endl; // n1 = 23784589493050034059009342324324
    	
    	Bign n2; 
    	n2 = 1234567890;
    	cout << " n2 = " << n2 << endl; // n2 = 1234567890
    	
    	Bign n3("9787827383654329"); 
    	cout << " n3 = " << n3 << endl; // n3 = 9787827383654329
    	
    	Bign n4(827383654); 
    	cout << " n4 = " << n4 << endl; // n3 = 827383654
    	
    	Bign n5 = "78398249420049293949589999999";
    	Bign n6 = "1344234769898495120000001"; 
    	cout << " n5 + n6 = " << (n5+n6) << endl; // n5 + n6 = 78399593654819192444710000000
    
    	Bign n7 = "7293949589999999";
    	Bign n8 = "14769896431116"; 
    	cout << " n7 * n8 = " << (n7*n8) << endl; // n7 * n8 = 107730880018080996672543568884
    											
    	 
    }