# 分数模板（C++模板）

update:真的有，而且在NOIP模拟赛里出现了！写double的卡精度到怀疑人生！

#include<bits/stdc++.h>
using namespace std;
namespace FlashHu{
#define RG register
#define I inline
#define R RG frac
#define OutputFormat 0
template<typename T>
T gcd(RG T a,RG T b){
return b?gcd(b,a%b):a;
}
template<typename T>
struct frac{
T a,b;

//initializations
I frac(){
a=(T)0;b=(T)1;
}
I frac(RG T x){
a=x;b=(T)1;
}
I frac(RG T x,RG T y){
a=x;b=y;
this->init();
}
I void init(){
assert(b);
if(b<0)a=-a,b=-b;
this->reduction();
}
I frac&operator=(RG T x){
a=x;b=1;
return*this;
}
I double to_double(){
return(double)a/b;
}

//arithmetic operation
I void reduction(){
RG T g=gcd(abs(a),b);
a/=g;b/=g;
}
I frac inv(){
assert(a);
return(frac){b,a};
}
I frac operator-(){
return(frac){-a,b};
}
I frac&operator++(){
a+=b;
return*this;
}
I frac&operator--(){
a-=b;
return*this;
}
I frac&operator+=(R x){
RG T g=gcd(b,x.b);
a=b/g*x.a+x.b/g*a;(b/=g)*=x.b;
this->reduction();
return*this;
}
I frac&operator-=(R x){
return*this+=-x;
}
I frac&operator*=(R x){
RG T g1=gcd(abs(a),x.b),g2=gcd(abs(x.a),b);
(a/=g1)*=x.a/g2;(b/=g2)*=x.b/g1;
return*this;
}
I frac&operator/=(R x){
return*this*=x.inv();
}
I frac friend operator+(R x,R y){
RG T g=gcd(x.b,y.b);
x=(frac){x.b/g*y.a+y.b/g*x.a,x.b/g*y.b};
x.reduction();
return x;
}
I frac friend operator-(R x,R y){
return x+-y;
}
I frac friend operator*(R x,R y){
RG T g1=gcd(abs(x.a),y.b),g2=gcd(abs(y.a),x.b);
(x.a/=g1)*=y.a/g2;(x.b/=g2)*=y.b/g1;
return x;
}
I frac friend operator/(R x,R y){
return x*y.inv();
}

//logic operations
I bool operator!(){
return!a;
}
I bool friend operator&&(R x,R y){
return x.a&&y.a;
}
I bool friend operator||(R x,R y){
return x.a||y.a;
}
I bool friend operator==(R x,R y){
return x.a==y.a&&x.b==y.b;
}
I bool friend operator!=(R x,R y){
return x.a!=y.a||x.b!=y.b;
}
#define logop(op)												\
I bool friend operator op(R x,R y){						\
return (x+-y).a op 0;								\
}
logop(<);logop(>);logop(<=);logop(>=);
#undef logop

//input and output
I friend istream&operator>>(RG istream&is,R&x){
x=0;
static string s;is>>s;
RG int pos=s.find_first_of('/');
if(~pos){
s[pos]=' ';
istringstream(s)>>x.a>>x.b;
x.init();
}
else istringstream(s)>>x.a;
return is;
}
I friend ostream&operator<<(RG ostream&os,R x){
os<<x.a;
if(OutputFormat||x.b!=1)os<<'/'<<x.b;
return os;
}
};
#undef RG
#undef I
#undef R
#undef OutputFormat
}

posted @ 2018-09-13 18:07  Flash_Hu  阅读(809)  评论(2编辑  收藏  举报