email.cpp

// Libraries.
#include <deque>
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
#include <cctype>

// Programmer-defined data types.
struct Email
{
  string line;
  string anEmail;
  string nonDup;
};

// Special compiler-dependent definitions.

// Global constants/variables.

// Programmer-defined functions.
void introduction(string objective); // Prototype introduction subprogram.
string getFile(string fileType, string dFileName); // Prototype file name input prompt subprogram.
bool isValidEmailChar(char c); // Prototype character validation subprogram.
string changeCase(string line); // Prototype string case conversion subprogram, assists in checking for duplicate addresses.
//string sortList(string line); // Prototype address sorting subprogram.
void readFile(string iFileName, string oFileName); // Prototype file reader subprogram.

int main()
{// Begin main.
  // Data. This is where all variables for each program/subprogram are declared.
  string objective = "Select an input and output file containing emails, and output the valid email addresses found to console."; // Program objective.
  string fileName; // User's input for both file name prompts.
  string dFileName = "fileContainingEmails.txt"; // Default file name for input, determined by programmer.
  string iFileName; // Input file name, determined by user.
  string oFileName; // Output file name, determined by user.
  string confirm; // This allows the user to continue program execution.

  // Introduction. Provides information about the program and its author. This is a prototype void function called to main.
  introduction(objective);

  // Prompt user for input file name and output file name.
  fileName = getFile("input", dFileName);
  if (fileName.length() == 0) // If Enter key is pressed, input file name will be program default, default file name will be program default.
  {
    iFileName = dFileName;
    dFileName = "copyPasteMyEmails.txt";
  }
  else
  {
    iFileName = fileName;
    dFileName = iFileName;
  }

  fileName = getFile("output", dFileName);
  if (fileName.length() == 0) // If Enter key is pressed, output file name will be program default or input file name depending on user input.
    oFileName = dFileName;
  else
    oFileName = fileName;
  cout << endl;

  // Output input and output file names to console. Pause program execution until Enter key is pressed.
  cout << "Input file name: " << iFileName << endl;
  cout << "Output file name: " << oFileName << endl << endl;

  while (true)
  {
    cout << "Press ENTER to continue: ";
    getline(cin, confirm);
    if (confirm.length() == 0) break;
    cout << endl;
  }
  cout << endl;

  // Output valid email addresses from selected input file to console and copy to output file.
  readFile(iFileName, oFileName);
}// End main.

void introduction(string objective)
{// Begin introduction.
  cout << "Objective: " << objective << endl;
  cout << "Programmer: Griffin (Last Name)\n";
  cout << "Editor(s) used: Notepad\n";
  cout << "Compiler(s) used: TDM MinGW\n";
  cout << "File: " << __FILE__ << endl;
  cout << "Complied: " << __DATE__ << " at " << __TIME__ << endl << endl;
}// End introduction.

string getFile(string fileType, string dFileName)
{
  string fileName;
  cout << "Enter a file name for " << fileType << " [Press ENTER to use default " << fileType << " file name (" << dFileName << ")]: ";
  getline(cin, fileName);
  return fileName;
}

bool isValidEmailChar(char c)
{// Begin isValidEmailChar.
  if ((c == '@') || (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c == '_') || (c == '-') || (c == '+') || (c == '.'))
    return true;
  else
    return false;
}// End isValidEmailChar.

string changeCase(string line)
{
  int i;

  for (i = 0; i < line.length(); i++)
  {
    line[i] = tolower(line[i]);
  }

  return line;
}

void readFile(string iFileName, string oFileName)
{
  ifstream fin; // This enables us to open the input file.
  ofstream fout; // This enables us to open the output file.
  int i = 0; // For-loop index.
  int s = 0; // Second loop index.
  int e = 0; // Third loop index.
  int j = 0;
  int k = 0;
  int invS = 0; // This will be the index of the first invalid character in a potential address.
  int invE = 0; // This will be the index of the second invalid character in a potential address.
  int dotPos; // The position of the period in the address.
  int count; // File output loop index.
  bool hasDot = false; // Checking to see if the address contains a period.
  bool duplicate = false; // Checking to see if the addresses has already been added to the list.
  deque<Email> addresses; // This will be our empty list.
  Email file; // This is our Email variable.

  cout << "Email addresses on file: " << endl;
  cout << "------------------------" << endl;
  fin.open(iFileName.c_str());
  if (!fin.good()) throw "I/O error";
  while (fin.good())
  {
    getline(fin, file.line);
    for (i = 0; i < file.line.length(); i++)
    {
      if (file.line[i] == '@') // If the email address on file has an @ character in it, is is considered valid and will be output to console.
      {
        for (s = i; s >= 0; s--)
        {
          if (!isValidEmailChar(file.line[s])) break;
        }
        invS = s + 1;
        s++;
        for (e = i; e < file.line.length() + 1; e++)
        {
          if (!isValidEmailChar(file.line[e]))
          {
            invE = e;
            break;
          }
          if (file.line[e] == '.') // If the email address on file has an @ and a period after it, it is considered valid.
          {
            dotPos = e;
            hasDot = true;
          }
        }
        file.anEmail = file.line.substr(invS, invE - invS);
        file.nonDup = changeCase(file.anEmail);
        for (j = 0; j < addresses.size(); j++)
        {
          for (k = j + 1; k < addresses.size(); k++)
          {
            if (addresses[j].nonDup == addresses[k].nonDup)
              duplicate = true;
            else
              duplicate = false;
          }
        }
        if ((s < i) && (e > i) && (hasDot == true) && (dotPos > i + 1) && (duplicate == false))
        {
          cout << file.anEmail << endl;
          addresses.push_back(file);
        }
      }
    }
  }
  fin.close();
  if (addresses.size() == 0)
    cout << "No email addresses were found on this file." << endl;
  else
  {
    cout << addresses.size() << " valid email addresses were found on file and were copied to " << oFileName << "." << endl;
    cout << "To view these email addresses, open " << oFileName << "." << endl;
  }
  cout << "------------------------";

  // Output all valid email addresses found to the user's selected output file.
  if (addresses.size() > 0)
  {
    fout.open(oFileName.c_str());
    for (count = 0; count < addresses.size(); count++)
    {
      if (count == addresses.size() - 1)
        fout << addresses[count].anEmail;
      else
        fout << addresses[count].anEmail << "; ";
    }
    fout.close();
  }
}