//the program has been used to 
 
//to find out the paleo-oil column height under a sample point 
 
//written by Zeng H.S 2006/08/11  
 
#include <iostream> 
 
using namespace std; 
 
main() 
 
{ 
 
  double p,rw,ro,height,radius,it,delta_factor;//"it" means intefacial tention 
 
  float g=9.817,m=1.45; 
 
  unsigned int choose_n; 
 
  cout<<"According to your data, choose 1 or 2:"<<endl 
 
      <<"1)I have Pc(psi) already."<<endl 
 
    <<"2)I have only throat radius(micro-meter)."<<endl; 
 
  cin>>choose_n; 
 
  cout<<"You have chosen "<<choose_n<<endl 
 
      <<"Now let\'s begin:"<<endl 
 
    <<"----------------------------------------------"<<endl; 
 
  if(choose_n==2) 
 
  { 
 
    cout<<"Please enter the mean throat radius(micro-meter): "<<endl<<endl 
 
        <<"radius="; 
 
        cin>>radius; 
 
        cout<<"Please enter interfacial tension factor: "<<endl 
 
            <<"if you can not sure what it is, enter 370 dynes/cm"<<endl  
 
      <<"as its default"<<endl<<endl  
 
            <<"Delta_factor(dynes/cm)="; 
 
        cin>>delta_factor; 
 
        delta_factor=delta_factor/1000;    //transfered to unit N/m 
 
        radius=radius/1000000; 
 
    p=2*delta_factor*m/radius/10000;  //Pc (psi)   
 
         
 
  } 
 
  else if(choose_n==1) 
 
  { 
 
    cout<<"Please enter the Pc(psi): "<<endl<<"Pc="; 
 
        cin>>p; 
 
  } 
 
   
 
  cout<<endl<<"please enter Ro,Rw(g/cm^3)"<<endl 
 
            <<"|note: If you don\'t know please"<<endl 
 
             <<"enter 1.006 and 0.85 as defaults: "<<endl; 
 
    cout<<"Rw="; 
 
  cin>>rw; 
 
  cout<<"Ro="; 
 
  cin>>ro; 
 
  rw=rw*1000; 
 
  ro=ro*1000; 
 
  height=p*10000/(rw-ro)/g/m; 
 
  cout<<"Results: "<<endl; 
 
  cout<<"----------------------------------------------"<<endl; 
 
  cout<<"Rw="<<rw/1000<<"g/cm^3;"<<"Ro="<<ro/1000<<"g/cm^3"<<endl; 
 
  cout<<"Pc= "<<p<<"psi"<<endl; 
 
  cout<<"paleo-oil column height= "<<height<<"m"<<endl; 
 
  cout<<"----------------------------------------------"<<endl; 
 
  cout<<"the end of the program, please press any key to quit"<<endl 
 
      <<"see you next time  ^___^)"<<endl; 
 
  system("pause");//stop to checking answer   
 
}