POJ 3299 Humidex 难度:0

题目链接:http://poj.org/problem?id=3299

#include <iostream>
#include <iomanip>
using namespace std;
double exp(double x){
    double ans=1;
    double td=1;
    for(int i=1;i<120;i++){
        td=td*x/i;
        ans+=td;
    }
    return ans;
}
 const double ine= 2.718281828 ;
double ln(double x){
    double ans=0;
   while(x<-1||x>1){
    ans++;
    x=(x+1)/ine-1;
   }
    double td=-1;
    for(int i=1;i<120;i++){
        td*=-x;
        ans+=td/(double)i;
    }
    return ans;
}
double t,d,h,temp;
int flag;
int main(){
    ios::sync_with_stdio(false);
    char st[9];
    while(cin>>st){
        flag=0;
        if(st[0]=='E'){
            break;
        }
        cin>>temp;
        if(st[0]=='T'){
                flag+=1;
                t=temp;
        }
        else if(st[0]=='D'){
                flag+=2;
                d=temp;
        }
        else if(st[0]=='H'){
                flag+=3;
                h=temp;
        }
        cin>>st;
        cin>>temp;
        if(st[0]=='T'){
                flag+=1;
                t=temp;
        }
        else if(st[0]=='D'){
                flag+=2;
                d=temp;
        }
        else if(st[0]=='H'){
                flag+=3;
                h=temp;
        }
        if(flag==3) h=t-5.555+0.555*6.11*exp(5417.7530* ((1/273.16) - (1/(d+273.16))));
        else if(flag==4) {
                double e=((h-t)/0.5555)+10.0;

                double td=ln((e/6.11)-1);
                d=1.0/((1.0/273.16)-td/5417.7530)-273.16;
        }
        else t= h+ 5.555- 0.555*6.11*exp(5417.7530* ((1/273.16) - (1/(d+273.16))));
        cout<<"T "<<setiosflags(ios::fixed)<<setprecision(1)<<t<<" D "<<d<<" H "<<h<<"\n";
    }
    return 0;
}