I'm having trouble with a homework assignment. 

Everything works as expected except for the `letter_grade` part. I'm not getting any compile errors, but every time I run the program, the `letter_grade` is -858993460. I know it's probably something simple that I am overlooking, but I've hit a wall and am pretty much out of ideas.

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

// Class Declaration

class StudentRecord
{
  string id;
  int A, B, C, D, F, grade;
  float avg, exam1, exam2;

public: 
  void input();
  void output();
  void average();
  void letter_grade();
};

// Gathering data

void StudentRecord::input()
{

  cout << " Please enter your student ID: ";
  cin >> id;
  cout << "\n";
  cout << " Enter your score for exam 1: ";
  cin >> exam1;
  cout << "\n";
  cout << " Enter your score for exam 2: ";
  cin >> exam2;
}

// Calculations

void StudentRecord::average()
{
  avg = (exam1 + exam2) / 2;
}

void StudentRecord::letter_grade()
{
  if ((avg >= 90) && (avg <= 100))
    grade = A;
  else if ((avg >= 80) && (avg < 90))
    grade = B;
  else if ((avg >= 70) && (avg < 80))
    grade = C;
  else if ((avg >= 60) && (avg < 70))
    grade = D;
  else (avg < 60);
  grade = F;
}

// Output Data

void StudentRecord::output()
{
  cout << "\n\n";
  cout << " *** Student Record ***" << endl;
  cout << "\n";
  cout << " Student ID: " << id << endl;
  cout << "\n";
  cout << " Grade for exam 1: " << exam1 << endl;
  cout << "\n";
  cout << " Grade for exam 2: " << exam2 << endl;
  cout << "\n";
  cout << " Average for the class: " << avg << endl;
  cout << "\n";
  cout << " Letter grade for the class: " << grade << endl;
  cout << "\n\n";
}

int main()
{
  StudentRecord student;
  student.input();
  student.average();
  student.letter_grade();
  student.output();

  system ("pause");
  return 0;
}

```