#include <iostream>
#include <fstream> // Library for I/O commands
#include <cstdlib>
using namespace std;

int change_file(ifstream&, ofstream&, char, char);

//This is Lab #4.
//The objections of this lab is to learn how to write an program that reads from a file.
//
int main()
{
	int return_counter;
	char pick, mypick;
	ifstream fin;
	ofstream fout;

	fin.open("lab4.txt"); //A call to open the file labeled "lab4.txt" which is the input file.
	if (fin.fail ()) //This is the error checking code to display on the screen if the file has opened or not.
	{
		cout << "In stream file has FAILED to open." << endl; //Statement if file failed to open.
		exit (1);
	}
	else
		cout << "File : lab4.txt has been opened successfully!" << endl; //Statement if the file opened successfully.
	
	fout.open("myFile.txt");
	if (fout.fail ( ))//Error code to check if file opened or not.
	{ 
		cout << "Out stream has FAILED to open!" << endl;//Statement if file failed to open.
		exit (1);
	}
		cout << "File : myfile.txt. has been opened successfully!" << endl;

	cout << "Which character do you want to change?" << endl; //Asking the user what to change.
	cin  >> pick;//Character that user wants to change.
	cout << "What character do you want to change it as?" << endl; //Asking the user what to change it as.
	cin  >> mypick;//Character user what to change it as.


	return_counter = change_file(fin, fout, pick, mypick); //CAll to reference the definition. From Part 2.

	cout << pick <<" Was changed to " << mypick <<" " << return_counter << "times" <<endl;
	//Final statement of Lab #4 claiming what character was changed to what, and how many times it has been changed.
	fin.close();
	fout.close();
	return 0;
}

int change_file(ifstream& in_stream, ofstream& out_stream, char q, char w)
{
//Beginning of Part 2 in function definition for the statement above.	
	int counter = 0;
	char next;

	
	in_stream.get(next);//Statement that changed the letters to the desired character the user has inputed.
	while (! in_stream.eof( ))
	{
		if( next == q)
		{
			out_stream << w;
			counter++;
		}
		else 
			out_stream << next;
			in_stream.get(next);
	}	
	return (counter);
	
}