Question

The __ member function returns a file's current read position.

Short answer

Answer: To use the "tellg()" member function in C++, perform the following steps: 1. Include header files: Include the "iostream" for input/output operations and "fstream" for file handling operations. 2. Open a file for reading: Open a file using an ifstream object. 3. Check if the file is open: Make sure the file is open before performing any read operations. 4. Use "tellg()" to get the current read position: Call the "tellg()" function on the input file stream object. 5. Output the current read position: Display the current read position to the user. 6. Close the file: Close the file after performing the required operations. Here's an example: ```cpp #include #include int main() { std::ifstream inputFile("file.txt", std::ios::in); if (!inputFile.is_open()) { std::cerr << "Error opening file" << std::endl; return 1; } std::streampos currentPosition = inputFile.tellg(); std::cout << "Current read position: " << currentPosition << std::endl; inputFile.close(); return 0; } ```

Step-by-step solution

Include necessary headers

Include the necessary header files, such as "iostream" for input/output operations and "fstream" for file handling operations in C++. ```cpp #include #include ```

Open a file for reading

Open a file using an input file stream (ifstream) object. Replace "file.txt" with the name of your file. ```cpp std::ifstream inputFile("file.txt", std::ios::in); ```

Check if the file is open

Ensure the file is open before performing any read operations. If the file is not open, display an error message and exit the program. ```cpp if (!inputFile.is_open()) { std::cerr << "Error opening file" << std::endl; return 1; } ```

Use the "__" member function to get the current read position

The member function used to get the current read position in a file in C++ is called "tellg()". To get the current read position, call the "tellg()" function on the input file stream object. ```cpp std::streampos currentPosition = inputFile.tellg(); ```

Output the current read position

Display the current read position to the user. ```cpp std::cout << "Current read position: " << currentPosition << std::endl; ```

Close the file

Close the file after performing the required operations. ```cpp inputFile.close(); ```

Full Example

Here's the complete program in C++ that demonstrates how to use the tellg() member function to get the current read position of a file. ```cpp #include #include int main() { std::ifstream inputFile("file.txt", std::ios::in); if (!inputFile.is_open()) { std::cerr << "Error opening file" << std::endl; return 1; } std::streampos currentPosition = inputFile.tellg(); std::cout << "Current read position: " << currentPosition << std::endl; inputFile.close(); return 0; } ```