Writing to Files

To write data to a file in C++, you can use the ofstream class from the fstream library. The ofstream class provides functions to write data to a file.

Here's an example code that demonstrates how to write data to a file using ofstream:

1#include <iostream>
2#include <fstream>
3
4int main() {
5  std::ofstream file("example.txt");
6
7  if (file.is_open()) {
8    file << "Hello, World!";
9    file.close();
10    std::cout << "Data written to file." << std::endl;
11  } else {
12    std::cout << "Unable to open file" << std::endl;
13  }
14
15  return 0;
16}

In the code above, we include the necessary libraries iostream and fstream. We then declare an ofstream object named file and pass the name of the file we want to write to as a parameter.

Inside the if statement, we check if the file is successfully opened using the is_open() function. If the file is open, we use the << operator to write the data Hello, World! to the file. We then close the file using the close() function and print a success message to the console.

If the file cannot be opened, we print an error message. It's important to handle such cases to prevent errors in your program.

This code demonstrates how to write data to a file in C++. You can modify it to write different data types or multiple lines of data.

Keep in mind that writing to a file will overwrite any existing data in the file. If you want to append data to an existing file, you can use the ofstream class with the ios::app flag.

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#include <iostream>

#include <fstream>

​

int main() {

  std::ofstream file("example.txt");

​

  if (file.is_open()) {

    file << "Hello, World!";

    file.close();

    std::cout << "Data written to file." << std::endl;

  } else {

    std::cout << "Unable to open file" << std::endl;

  }

​

  return 0;

}