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

using namespace std;

struct element
{ int atno;
  string sym, name;
  double atwt;

  element(int an, string sy, string nm, double aw)
  { atno = an;
    sym = sy;
    name = nm;
    aw = atwt; }

  void print()
  { cout << "(" << atno << ", " << atno << ", '"
         << sym << "', '" << name << "', " << atwt << ")"; } };

element makeel(int an, string sy, string nm, double aw)
{ element e;
  e.atno = an;
  e.sym = sy;
  e.name = nm;
  e.atwt = aw;
  return e; }

int read_table(element pt[])
{ ifstream inf;
  inf.open("/home/www/class/een118/a3010b.txt");
  if (inf.fail())
  { cerr << "Can't open file\n";
    exit(1); }
  int atno = 0;
  while (true)
  { string sym, name;
    double atwt;
    inf >> sym >> name >> atwt;
    if (inf.fail())
      break;
    atno += 1;
    element e(atno, sym, name, atwt);
    pt[atno] = e; }
  pt[0] = makeel(0, "XXX", "XXXXXXXXX", 0.0);
  inf.close();
  return atno; }

element findel(string sy, element pt[], int n)
{ for (int i = 1; i <= n; i += 1)
    if (pt[i].sym == sy)
      return pt[i];
  return pt[0]; }

int main()     // this function has grown far too big
{ string sym, name;
  double atwt;
  element pt[120];
  
  int atno = read_table(pt);
  
  const int entries = atno;
  for (atno = 1; atno <= entries; atno += 1)
  { pt[atno].print();
    cout << "\n"; }

  double molwt = 0;
  int num;
  while (true)
  { cout << "> ";
    cin >> sym;
    if (cin.fail())
      break;

    element e = findel(sym, pt, entries);
    if (e.atno == 0)
    { cout << "'" << sym << "' not found\n";
      break; }

    cout << "number? ";
    cin >> num;
    e.print();
    cout << " * " << num << "\n";
    molwt += e.atwt * num; }

  cout << "Molecular weight " << molwt << "\n"; }