std::ofstream file1(FILE_NAME, std::ios::app);

The code snippet you provided is written in C++ and involves the use of the std::ofstream class. The purpose of this code is to create a file stream object and open a file with a specific name in append mode.

Let's break down the code step by step:

Step 1: Include the necessary header file

Before using the std::ofstream class, you need to include the appropriate header file, which is <fstream> in this case. This header file provides the necessary definitions and declarations for file stream operations.

#include <fstream>

Step 2: Declare the file stream object

In this step, a file stream object named file1 is declared. The std::ofstream class is used for creating an output file stream. The name of the file to be opened is specified as the first argument, FILE_NAME, which is a placeholder for the actual file name.

std::ofstream file1;

Step 3: Open the file in append mode

To open the file in append mode, the open() function of the std::ofstream class is used. It takes two arguments: the file name and the open mode. The std::ios::app flag is used as the open mode, which stands for "append".

file1.open(FILE_NAME, std::ios::app);

The std::ios::app flag ensures that any output performed on the file will be appended to the existing content of the file, rather than overwriting it. If the file doesn't exist, a new file will be created.

Final code:

Putting it all together, the code snippet you provided can be written as follows:

#include <fstream>

std::ofstream file1;
file1.open(FILE_NAME, std::ios::app);

This code declares a file stream object named file1 and opens a file with the specified name in append mode using the std::ios::app flag.