File Handling : MCQs & PYQs with Explanation

Option D

In C++, file handling is performed using file stream classes available in the <fstream> header file. Different stream classes are used for different types of file operations.

• The fstreambase class provides functions that are common to all file stream classes, such as opening and closing files.
• The ifstream class is used for input operations, meaning it reads data from a file.
• The ofstream class is used for output operations, meaning it writes data to a file.
• The fstream class supports both input and output operations simultaneously.

Option B

In C++, when working with files, the open() method of file streams allows you to specify the mode in which the file should be opened.

• It is possible to combine two or more file opening modes using the bitwise OR operator (|). For example, fstream file("myfile.txt", ios::in | ios::out); opens a file for both reading and writing. Therefore, statement 1 is incorrect, and statement 2 is correct.
• The ios::in is used to open a file in input (reading) mode and ios::out is used to open a file in output (writing) mode. So, statement 3 is correct.

Option C

In C++, file streams use modes to control how files are opened and accessed. The ios::trunc is a file mode used with output streams. Its purpose is to truncate an existing file, which means it deletes all the current content of the file and makes its size zero before writing new data.

• If the file does not exist, it will be created.
• Usually, ios::trunc is used with ios::out mode while opening a file for writing.

#include <fstream>
using namespace std;
int main() {
    ofstream file("myfile.txt", ios::out | ios::trunc);
    file<<"New Content Added.";
    file.close();
    return 0;
}