ifstream object.eof()不起作用

#include<iostream>
#include <fstream>

int main() {
    std::ifstream input_file("example.txt");
    int data;

    while (input_file >> data) {
        std::cout << "Read data: "<< data<< std::endl;
    }

    if (input_file.eof()) {
        std::cout << "End of file reached."<< std::endl;
    } else {
        std::cout << "Error occurred while reading the file."<< std::endl;
    }

    input_file.close();
    return 0;
}