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

using namespace std;

int main()
{ ifstream fin;
  fin.open("table.txt");
  if (fin.fail())
  { cout << "Couldn't open 'table.txt'\n";
    exit(1); }
    // exit stops program from anywhere
  double total = 0.0;
  while (true)
  { string wanted;
    cout << "Enter symbol: ";
    cin >> wanted;
    if (wanted == "end")
      break;
    int atno = 0;
    fin.seekg(0, ios::beg);  // reposition to 0 bytes from beginning
    while (atno < 111)
    { string symbol, name; 
      double atwt;
      fin >> symbol >> name >> atwt;
      if (fin.fail())   // not error, just end of file
        break;
      atno = atno + 1;
      if (symbol == wanted)
      { cout << atno << ": " << name << " (" << symbol
             << ") wt = " << atwt << endl;
        total = total + atwt;
        break; } } }
  fin.close();
  cout << "Molecular weight = " << total << endl; }