// pgm36
// This is today's lab. We are going to practice programming
// with strings, including passing strings as parameters
// and returning strings from functions.
// 11/23/2016

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;
int countOcc(string, string);
void erasepart(string &);
int main()
{
  int choice;
  string line, sub;
  ifstream infile("stringdata.txt");
  getline(infile, line);
  cout << "text is: " << endl << line << endl;
  // Write a program that reads in a text,
  // gives the user a menu to modify or search the text
  // as many times as the user wants to.
  // menu
  do {
    cout << "1. Search text for a pattern." << endl;
    cout << "2. Erase a part of the text." << endl;
    cout << "3. Replace a part of the text." << endl;
    cout << "4. Insert a string into the text." << endl;
    cout << "5. Exit" << endl;
    cout << "Enter choice:";
    cin >> choice;
    if (choice==1) {
        cout << "Enter string to search for: ";
        cin >> sub;
        cout << countOcc(line, sub) << " were found." << endl;
    }
    else if (choice==2) {
        erasepart(line);
    }
    else if (choice==3) ; // do on your own
    else if (choice==4) ; // do on your own
    cout << "Text is currently: " << endl;
    cout << line << endl;
  } while (choice!=5);

  return 0;
}


// this function counts how many times a substring occurs
// in a bigger string
// the function accepts substring to search for, bigger string
// the function returns an int which is the count
// count how many times the pattern occurs in the text
int countOcc(string text, string pattern)
{
  size_t pos=text.find(pattern);
  int numocc=0;
  while(pos!=string::npos) {
    numocc++;
    pos=text.find(pattern,pos+1);
  }
  return numocc;
}

// function erasepart allows the user to erase part of
// the string parameter.
void erasepart(string &str)
{
   string sub;
   cout << "What substring do you want to erase? ";
   cin >> sub;
   size_t pos = str.find(sub, 0);
   if (pos!=string::npos) // found it!
       str.erase(pos, sub.length());
   else
       cout << sub << " not found in text." << endl;
}