Reading the next line

[Eli1001]

I have a nearly completely functional bit of code, with one roadblock due to my lack of experience. This code is supposed to read from a file and tell what the general state of a person's blood pressure is.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main () {
	char yes;
  ifstream myfile;
  string lastname;
  string firstname;
  int sys;
  int dia;
  myfile.open ("patient.dat");
  myfile >> lastname>>firstname>>sys; 
  myfile.ignore(1,'/');
  myfile >> dia;
  do{ if (sys<=119 && dia <=79)
	  cout << lastname << ", "<< firstname << " has normal blood pressure at " << sys <<"/"<< dia <<endl;
  else if (sys>= 120 && sys<=139 || dia>=80 && dia<=89)
cout << lastname << ", "<< firstname << " has prehypertension at " << sys <<"/"<< dia <<endl;
  else if (sys>= 140 && sys<=159 || dia>=90 && dia<=99)
cout << lastname << ", "<< firstname << " has Stage 1 high blood pressure at " << sys <<"/"<< dia <<endl;
  else cout << lastname << ", "<< firstname << " has Stage 2 high blood pressure at " << sys <<"/"<< dia <<".\n";
cout<< "Next patient? Y/N ";
  cin>>yes;} while (yes=='y' || yes=='Y');
	return 0;
}

My issue arises in that I do not know how to make it read the next line in the data file, which looks like this:

Smith Eli 110/73
Johns Thomas 200/78

And so on til the end of the file.
Can I get any help?