5.2.3 高精度运算类bign
#include<stdio.h>
#include<string.h>
#include<math.h>
const int maxn=1000;
struct bign
{
int len,s[maxn];
bign()
{memset(s,0,sizeof(s));len=1;}
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 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;
}
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;
}
};
istream& operator >> (istream &in,bign& x)
{
string s;
in>>s;
x=s.c_str();
return in;
}
ostream& operator >> (ostream &in,bign& x)
{
out<<x.str();
return out;
}
int main()
{
return 0;
}