#include <iostream>
#include <fstream>
#include <string>

using namespace std;

bool isnum(string s)
{ const int len = s.length();
  int i = 0;
  while (i < len)
  { char c = s[i];
    if (c < '0' || c > '9')
      return false;
    i = i + 1; }
  return true; }

const int arrsize = 120;
string names[arrsize], symbols[arrsize];
double atwts[arrsize];

int read_elements()
{ ifstream fin;
  fin.open("/home/www/class/een118/a3010b.txt");
  if (fin.fail())
  { cout << "Can't read file\n";
    exit(1); }

  int atno = 0;
  while (atno < arrsize - 1)
  {
    string symbol, name;
    double atwt;
    fin >> symbol >> name >> atwt;
    if (fin.fail())
      break;

    atno = atno + 1;

    symbols[atno] = symbol;
    names[atno] = name;
    atwts[atno] = atwt;
  }
  cout << atno << " Elements successfully read\n";
  fin.close();
  return atno; 
}

int find_elem(string sym, int numels)
{ int i = 1;
  while (i <= numels)
  { if (sym == symbols[i])
      return i;
    i = i + 1; }
  return 0; }      // 0 means not found

int main()
{
  int numels = read_elements();
  double molwt = 0.0;
  cout << "Enter a formula: ";
  bool ok = true;

  while (true)
  { string s;
    cin >> s;

    if (s == ".")
      break;

    int an = find_elem(s, numels);
    if (an == 0)
    { cout << s << ": No such element\n";
      ok = false;
      continue; }

    cout << an << ", ";
    cout << symbols[an] << ", ";
    cout << names[an] << ", ";
    cout << atwts[an] << "\n";
    molwt = molwt + atwts[an]; }

  if (ok)
    cout << "Molecular weight = " << molwt << "\n";
  else
    cout << "There was an error in the input\n";
}