MoreFileInOutDEMO.cpp

//************************************************************************
// Author: Rolando Carreon
// Date: apr 1 2025
// Language: C++
// Assignment: More File In Out DEMO
// Description: create a file, read the file, and read/write a file
//************************************************************************

#include<iostream>
#include<fstream>
#include <string>
using namespace std;

int main()
{
    // declare local variables
    ofstream myOutFile("example.txt");
    
    //cehck if the file opens successfull
    if ( myOutFile.is_open() )
    {
        // write to the file
        myOutFile << "Hello World!\n";
        myOutFile << "This is a C++ file writing example\n";
        
        myOutFile.close(); // close the file
    }
    else
        cout << "Unable to open the file for writing.\n";
    
    
    
    //----------------------------
    // declare local variables
    fstream myInFile ("example.txt");
    string line;
    
    // check if the file opens successfully
    if ( myInFile.is_open() )
    {
        // loop through the file reading/ displaying one line ar a time
        // exits loop if failstate occurs like file never opened
        while ( getline(myInFile, line) )
        {
            cout << line << "\n";
        }
        
        myInFile.close(); // close the file
        
    }
    else
        cout << "Unable to open file for reading.\n";
    
    //----------------------------------------------------
    // declare local variables
    // overloading - read in | write out, might need .append
    fstream myFile("example.txt", ios::in | ios::out);
    string line2;
    
    // check if the file opened successfully
    if (myFile.is_open())
    {
        
        // loop through the file reading/ displaying one line ar a time
        // exits loop if failstate occurs like file never opened
        while ( getline(myFile, line2) )
        {
            cout << line2 << "\n";
        }
        
        //clears failed states like the while loop
        myFile.clear(); // clear any error flags
        // seekp sets line to line0 and the ios beg sets to begging of line
        myFile.seekp(0, ios::beg);
        
        myFile << "New Content added.\n";
        
        myFile.close();
        
        
    }
    else
        cout << "Unable to open the file.\n";
    
    
    return 0;
}