#include "library.h"

int sumsquares(int first, int last)
{ if (first > last)
    return 0;
  return first*first + sumsquares(first+1, last); }

bool ask(string q)
{ print(q);
  print("? ");
  const string s = read_string();
  if (s == "yes" || s == "y" || s == "Y")
    return true;
  return false; }

void test()
{ print("enter a: ");
  const int a = read_int();
  print("enter N: ");
  const int n = read_int();
  print("sum of squares from ");
  print(a);
  print(" to ");
  print(n);
  print(" is ");
  print(sumsquares(a, n));
  new_line(); }
 
void main()
{ test();
  const bool again = ask("do you want another go");
  if (again)
    main(); }