URAL 1823 Ideal Gas

 1 #include <iostream>
 2 #include <string.h>
 3 #include <iomanip>
 4 #include <algorithm>
 5 using namespace std;
 6 double R = 8.314;
 7 int a[5];
 8 char s1[10],s2[10];
 9 int init(char str[10])
10 {
11     if(str[0]==‘p‘) return 1;
12     else if(str[0]==‘V‘) return 2;
13     else if(str[0]==‘n‘) return 3;
14     else if(str[0]==‘T‘) return 4; 
15 }
16 void f()
17 {
18     if(a[1]==0 && a[3]==0) cout<<"undefined"<<endl;
19     else if(a[1]==0 && a[3]!=0)
20     {
21         if(a[2]==-1) cout<<"error"<<endl;
22         if(a[3]==-1) cout<<"n = 0"<<endl;
23         if(a[4]==-1) cout<<"error"<<endl;
24     }
25     else if(a[1]!=0 && a[3]==0)
26     {
27         if(a[1]==-1) cout<<"p = 0"<<endl;
28         if(a[2]==-1) cout<<"error"<<endl;
29         if(a[4]==-1) cout<<"error"<<endl;
30     }
31     else if(a[1]!=0 && a[3]!=0)
32     {
33         if(a[1]==-1) cout<<"p = "<<setiosflags(ios::fixed)<<setprecision(6)<<(double)a[3]*a[4]*R/a[2]<<endl;
34         if(a[2]==-1) cout<<"V = "<<setiosflags(ios::fixed)<<setprecision(6)<<(double)a[3]*a[4]*R/a[1]<<endl;
35         if(a[3]==-1) cout<<"n = "<<setiosflags(ios::fixed)<<setprecision(6)<<(double)a[1]*a[2]/(R*a[4])<<endl;
36         if(a[4]==-1) 
37             cout<<"T = "<<setiosflags(ios::fixed)<<setprecision(6)<<(double)a[1]*a[2]/(R*a[3])<<endl;
38     }
39     
40 }
41 int main()
42 {
43     
44     int x;
45     int t;
46     while(cin>>s1>>s2>>t)
47     {
48         memset(a,-1,sizeof(a));
49         x = init(s1);
50         a[x] = t;
51         cin>>s1>>s2>>t;
52         x = init(s1);
53         a[x] = t;
54         cin>>s1>>s2>>t;
55         x = init(s1);
56         a[x] = t;
57         f();
58     }
59     return 0;
60 }