push_back on a vector crashing

[Paul McKenzie]

For an example:

#include <algorithm>

bool isPassingGrade(const Student_info& info)
{
    return !fgrade(info);
}

vector<Student_info> extract_fails(vector<Student_info>& students)
{
    // Partition students -- passing is on left of partition, failing is on right of partition
    vector<Student_info>::iterator it = std::stable_partition(students.begin(), students.end(), isPassingGrade);

    // iterator "it" is the partition point, so erase failures starting there
    students.erase(it, students.end());
    return students;
}

All of that code that you're writing is in those few lines.

Regards,

Paul McKenzie