Prompt Title: C++ File Handling.

In C++, file handling is an essential concept that enables programs to read from and write data to files. A file is a collection of data that is stored on a storage device like a hard disk or a solid-state drive. File handling in C++ involves opening, reading, writing, and closing files. There are two types of files in C++: text files and binary files. Text files are files that contain ASCII characters and can be read and edited using a text editor. Binary files, on the other hand, contain data in a binary format that is not human-readable and require specialized software to read and edit. To perform file handling in C++, you must include the fstream library. The fstream library provides classes for file handling operations like opening, reading, writing, and closing files. The two main classes provided by the fstream library are ifstream and ofstream. The ifstream class is used to read data from a file, while the ofstream class is used to write data to a file. To open a file for reading or writing, you must create an object of the appropriate class and specify the filename and mode of operation. There are three modes of operation in file handling in C++: 1. ios::in - This mode is used to open a file for reading. 2. ios::out - This mode is used to open a file for writing. 3. ios::app - This mode is used to open a file for appending. To open a file for reading, you can use the following code: ``` #include <fstream> using namespace std; int main() { ifstream infile; infile.open("example.txt", ios::in); if (!infile) { cout << "Cannot open file!" << endl; return 1; } // read data from the file infile.close(); return 0; } ``` In the code above, we first create an object of the ifstream class called infile. We then call the open() method of the infile object and specify the filename and mode of operation as ios::in. If the file cannot be opened, the code outputs an error message and returns an error code. To open a file for writing, you can use the following code: ``` #include <fstream> using namespace std; int main() { ofstream outfile; outfile.open("example.txt", ios::out); if (!outfile) { cout << "Cannot open file!" << endl; return 1; } // write data to the file outfile.close(); return 0; } ``` In the code above, we first create an object of the ofstream class called outfile. We then call the open() method of the outfile object and specify the filename and mode of operation as ios::out. If the file cannot be opened, the code outputs an error message and returns an error code. To append data to an existing file, you can use the following code: ``` #include <fstream> using namespace std; int main() { ofstream outfile; outfile.open("example.txt", ios::app); if (!outfile) { cout << "Cannot open file!" << endl; return 1; } // append data to the file outfile.close(); return 0; } ``` In the code above, we first create an object of the ofstream class called outfile. We then call the open() method of the outfile object and specify the filename and mode of operation as ios::app. If the file cannot be opened, the code outputs an error message and returns an error code. To read data from a file, you can use the following code: ``` #include <fstream> using namespace std; int main() { ifstream infile;