// Read in a roster, find average grades for each line.
// Michael Rothstein
// 07/22/2014

#include <iostream>
#include <cstdlib>
const int MAXNUM_Students=100,MAXNUM_Grades=20;

int grades[MAXNUM_Students][MAXNUM_Grades+1];
int num_students=0,num_grades=0;

using std::cin; using std::cout; using std::endl; using std::cerr;

void read_in();

void do_averages(double avgs[]);

int main(){
  double averages[MAXNUM_Students];
  read_in();
  do_averages(averages);
  cout << "These are the averages:\n";
  for(int i=0;i<num_students;i++){
    cout << grades[i][0] << ' ' << averages[i] << endl;
  }
  return 0;
}

void read_in(){
  cout << "How many students and how many grades are there? ";
  cin >> num_students >> num_grades;
  if ( num_students <= 0 || num_grades <= 0) {
    cerr << "Come on, you must be joking! Non-positive data! Yeah!\n";
    exit(1);
  }
  if ( num_students > MAXNUM_Students) {
    cerr << "Sorry, I cannot handle that many students!\n";
    exit(1);
  }
  if ( num_grades > MAXNUM_Grades ) {
    cerr << "Sorry, I cannot handle that many grades!\n";
    exit(1);
  }
  for ( int i = 0; i < num_students; i++){
    cout << "Please give me ID number and grades for student " << i+1 << ' ';
    for (int j=0; j <= num_grades; j++ ) cin >> grades[i][j];
  }
}

void do_averages(double avg[]){
  for(int i=0;i<num_students;i++){
    int sum = 0;
    for(int j=1;j<=num_grades;j++)
      sum += grades[i][j];
    avg[i] = double(sum)/num_grades;
  }
}