IS_OPEN()

The is_open() function is a member of file stream classes such as ofstream, ifstream, and fstream, and it is used to check whether a file has been successfully opened. It returns a Boolean value true if the file is currently open and ready for read or write operations, or false if the file failed to open (for example, due to an invalid path, missing permissions, or a non-existent file). Using is_open() is an important step in safe file handling, as it allows you to verify that the file stream is valid before attempting to read from or write to it. This helps prevent runtime errors and ensures that your program handles file access issues gracefully.

#include <iostream>   // For console input/output (cout, cin, etc.)
#include <fstream>    // For file handling (ofstream, ifstream, etc.)
#include <string>     // For using the string data type

using namespace std;

int main() {
    // Step 1: Define the name of the file to open or create
    string filename = "example.txt";

    // Step 2: Declare an ofstream object for writing to files
    ofstream myFile;

    // Step 3: Attempt to open the file for writing
    // If the file does not exist, it will be created automatically.
    // If it already exists, its contents will be overwritten.
    myFile.open(filename);

    // Step 4: Check if the file was opened successfully
    if (myFile.is_open()) {
        cout << "File opened successfully!\n";

        // Step 5: Write data to the file (uncomment the line below to test)
        // myFile << "Hello, file!\n";

        // Step 6: Close the file to ensure data is saved and resources are freed
        myFile.close();
        cout << "File closed successfully.\n";
    } else {
        // Error handling if the file could not be opened
        cout << "Error opening file!\n";
    }

    return 0; // Indicate successful program termination
}