reading in lines from a file to a vector c++

#include <iostream>
#include <fstream>
#include <vector>
#include <string>

int main() {
    std::ifstream file("file.txt"); // Open file named "file.txt"
    std::vector<std::string> lines; // Create a vector to store lines from the file
    std::string line; // Create a string variable to hold each line

    if (file.is_open()) { // Check if the file is open
        while (std::getline(file, line)) { // Read lines from the file into 'line'
            lines.push_back(line); // Add 'line' to the vector 'lines'
        }
        file.close(); // Close the file
    } else {
        std::cout << "Unable to open file"; // Display error if file cannot be opened
    }

    // Display the contents of the vector 'lines'
    for (const auto &l : lines) {
        std::cout << l << std::endl;
    }

    return 0;
}