ZOJ 1241 求直角三角形第三边

//Geometry Made Simple
//求直角三角形第三边
#include<iostream.h>
#include<string.h>
#include<math.h>
#include<iomanip.h>
//using namespace std;

int main()
{
int shu[3],i,j=1;
char ch;
double chu;
while(cin>>shu[0]>>shu[1]>>shu[2])
{
if(shu[0]==0&&shu[1]==0&&shu[2]==0)
return 0;

cout<<"Triangle #"<<j<<endl;
for(i=0;i<=2;i++)
if(shu[i]==-1)
{
ch='a'+i;
break;
}
if(i==2)
{
chu=pow(shu[0],2)+pow(shu[1],2);
cout<<ch<<" = "
<<setiosflags(ios::fixed)<<setprecision(3)
<<sqrt(chu)<<endl<<endl;
}
else
{
if(shu[1-i]>=shu[2])
cout<<"Impossible."<<endl<<endl;
else
{
chu=pow(shu[2],2)-pow(shu[1-i],2);
cout<<ch<<" = "
<<setiosflags(ios::fixed)<<setprecision(3)
<<sqrt(chu)<<endl<<endl;
}
}
j++;
}
return 0;
}