Program Implementation

[Nusc]

The following program is supposed to prompt the user for a student ID.
Open a text file.
Calculate the student's average GPA and print his transcript.

#include <fstream>
#include <vector>
#include <iostream>
#include <cmath>
#include <cstdlib>
 
using namespace std;
 
 
struct course
{
char session;
int year;
string coursename;
int coursenumber;
double percentage;
string lettergrade;
 
};
 
struct student
{
vector <course> courses;
string firstname;
string lastname;
int id;
};
 
 
void ReadStudent(string id, vector<student>& a);
void PrintTranscript(const vector<student>& a);
double ComputeGPA(const vector<student>& a);
int main()
{ 
string id;
string filename;
vector <student> a;
 
cout <<"Please enter your student ID number"<< endl;
cin >> id;
ReadStudent(id, a);
char choice;
 
do
{
cout << "What do you wish to do with the database?" << endl;
cout << "Input the relevant letter: Options are" << endl;
cout << "(a) List the courses taken by the student" << endl;
cout << "(b) Compute and display the student's grade point average (GPA)" << endl;
cout << "(c) Open the file of another student" << endl;
cout << "(d) Quit the program" << endl;
 
cin >> choice;
cout << "You have entered:" << choice << endl;
switch (choice)
{
case ('a'):
PrintTranscript(a);
break;
case ('b'):
ComputeGPA(a);
break;
case ('c'):
cout << "Please enter another student ID" << endl;
cin >> id;
ReadStudent(id,a);
break;
case ('d'):
{
cout << "Program ending" << endl;
}
}
}while(choice != 'd');
return 0;
}
 
void ReadStudent( string id,vector<student>& a)
{
student tmp;
id += ".txt";
ifstream infile(id.c_str());
infile >> tmp.firstname;
infile >> tmp.lastname;
infile >> tmp.id;
tmp.courses.resize(0);
while(!infile.eof())
{
//tmp.courses.push_back(tmp); 
int j = tmp.courses.size()-1;
infile >> tmp.courses.at(j).session;
infile >> tmp.courses.at(j).year;
infile >> tmp.courses.at(j).coursename;
infile >> tmp.courses.at(j).coursenumber;
infile >> tmp.courses.at(j).percentage;
infile >> tmp.courses.at(j).lettergrade;
a.push_back(tmp);
}
}
 
void PrintTranscript( const vector <student>& a )
{
cout << "Here is a list of courses that you have taken:" << endl;
for (int i = 0; i<a.size(); i++)
{
cout << a.at(i).firstname << " " << a.at(i).lastname << " " << a.at(i).id << endl;
for (int j = 0; j<a.size(); j++)
{
 
cout << a.at(i).courses.at(j).session << " " << a.at(i).courses.at(j).year << " " << a.at(i).courses.at(j).coursename << " " << a.at(i).courses.at(j).percentage << " " << a.at(i).courses.at(j).lettergrade << endl;
}
}
}
 
double ComputeGPA(const vector <student>& a)
{
double GPA = 0;
double sum = 0;
for(int j = 0; j<a.size(); j++)
{
for( int i = 0; i<a.at(j).courses.size(); i++)
{
if(a.at(j).courses.at(i).lettergrade == "A+")
sum += 4.0;
if(a.at(j).courses.at(i).lettergrade == "A")
sum += 4.0; 
if(a.at(j).courses.at(i).lettergrade == "A-")
sum += 3.7;
if(a.at(j).courses.at(i).lettergrade == "B+")
sum += 3.3;
if(a.at(j).courses.at(i).lettergrade == "B")
sum += 3.0;
if(a.at(j).courses.at(i).lettergrade == "B-")
sum += 2.7;
if(a.at(j).courses.at(i).lettergrade == "C+")
sum += 2.3;
if(a.at(j).courses.at(i).lettergrade == "C")
sum += 2.0;
if(a.at(j).courses.at(i).lettergrade == "C-")
sum += 1.7;
if(a.at(j).courses.at(i).lettergrade == "D")
sum += 1.0;
if(a.at(j).courses.at(i).lettergrade == "F")
sum += 0.0;
GPA = sum/a.at(j).courses.size();
}
}
 
cout << "Average GPA:" << GPA << endl;
return GPA;
}

the test file is:

123456.txt

John Smith 123456
F 2005 ENGG 205 62 C-
W 2006 ECON 209 79 B+
W 2006 ENGG 233 85 A


I get aborted (core dumped) when running the program.

I suspect it has to do with the read function, what's wrong?

[Nusc]

Where else can I get help?

[Nusc]

Does anyone know why?

The code compiles, but it doesn't run.