way to make the c++ read without using sentinel

[Omnia]

need a way to make my program read info like this.


i have this in my assignment:

1463491 Ali 4 72 65 81 85
1730005 Yousef 5 91 82 94 75 87
5437330 Amna 3 68 72 63
2600004 Abrat 4 52 83 74 66
1300002 Sadiq 2 72 61

i should make the program read the numbers from this file, as you can see there is no -999 or any sign after the numbers, and i'm not allowed to modify the folder to add any sentienl


so how can i make my program read that and stop????


i just reach chapter 11 which it classes.

     for (int i = 0 ; i < numOfStudents ; i ++)
    {
       fcin >>ID>>NAME;

       int y = 0 ;

       while (fcin)  // fcin is as ifstream fcin
       {
           fcin >> S_marks[y];

           y ++;

           cout <<endl<< S_marks[y]<<endl;
       }

       section[i].set(ID, NAME, S_marks ,y);
    }

[LB]

The sentinel for the grades is the end of the line.
The sentinel for the students is the end of the file.
When a C++ stream reaches the end and you try to extract data from it, it gets put into a failure state. You can simply check that failure state.

#include <iostream>
#include <vector>
#include <string>
#include <sstream>

struct Student
{
    int id;
    std::string name;
    std::vector<int> grades;

    friend std::istream &operator>>(std::istream &is, Student &s)
    {
        is >> s.id >> s.name;
        s.grades.clear();
        std::string grades;
        std::getline(is, grades);
        std::istringstream iss {grades};
        int grade;
        while(iss >> grade) //keep reading until no more greades
        {
            s.grades.push_back(grade);
        }
        return is;
    }
};

int main()
{
    std::ifstream ifs {"students.txt"};
    std::vector<Student> students;
    {
        Student s;
        while(ifs >> s) //see line 12
        {
            students.push_back(s);
        }
    }
    //...rest of your program...
}

EDIT: ne555 noticed that the number after the name might be the number of grades - in that case, use his solution, not mine.

[ne555]

I suppose that the number next to the name indicates the quantity of marks to be read
So

fin >> id >> name >> n;
marks.resize( n );
for(int K=0; K<n; ++K)
   fin >> marks[K];

If that is not the case, then you can read the line (till the '\n') and process it.

fin >> id >> name;

std::string line;
std::getline( fin, line );
std::istringstream input(line);

int foo;
while( input>>foo )
   marks.push_back( foo );

[Omnia]

i really appreciate what you did, but it's too advance.

this what i did in my program

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

const int sizeArray = 50;


struct personalInfo
{
    string id , name ;
};

class student
{
     private:
     personalInfo person;
     int numberOfCourses;
     float average ;
     int marks[sizeArray]; // an array of student's marks


     public:
     void set(string ,string ,int S_marks[] , int);
     void getPerson(string &, string& ) const;
     void print()const;
     void findAverage( );  //is used to calculate the average mark for each student.
     float getAverage( );
    // student (int = 1);

};

int maxAverageIndex(int, student [ ]);

int main ()
{
    ifstream fcin ;
    ofstream fout;

    fcin.open("student.txt");

    student section[sizeArray] ;
    int numOfStudents;
    int S_marks[sizeArray];
    string ID, NAME;


    cin>>numOfStudents;

    for (int i = 0 ; i < numOfStudents ; i ++)
    {
       fcin >>ID>>NAME;

       int y = 0 ;

       while (fcin) 
       {
           fcin >> S_marks[y];

           y ++;

        //  >>>>>>>>> cout <<endl<< S_marks[y]<<endl; this only to check and its just keep showing zeros
       }

       section[i].set(ID, NAME, S_marks ,y);
    }



for ( int i = 0 ; i < numOfStudents ; i ++)
{
    section[i].findAverage();
    section[i].print();
}



fcin.close();

    return 0 ;
}


void student::set(string ID,string NAME,int S_marks[], int y)
{
    person.id= ID;
    person.name = NAME;

    for (int u = 0 ; u < y ; u ++)
    {
        marks[u] = S_marks[u];
    }


 numberOfCourses = y;
}

void student::getPerson(string & ID, string & NAME ) const
{
    ID = person.id;
    NAME= person.name;
}

void student::findAverage( )
  {
      average= 0 ;
      for (int x= 0 ; x < numberOfCourses ; x ++)
      {
           average = average + marks[x];
      }

  }

void student::print ()const
{
    cout << "Student "<<person.name<<"  with id "<< person.id <<" has average "
    <<average<<" of "<<numberOfCourses+1 << "courses."<<endl;




    for ( int y = 0 ; y < 3 ; y ++)
    {

        cout << marks[y]<<"   ";
    }
    cout<<endl;
}

THERE is no number of the grades and this is the problem

[LB]

Maybe you missed ne555's post?

[Omnia]

yes and i didn't notice that the number after the name is for the number of the grades.


sorry about that.


NOW the problem is really easy. i thank you both ^^