c++如何检查参数流是否为空

#include <iostream>
#include <fstream>

bool isStreamEmpty(std::istream& stream) {
    return stream.peek() == std::ifstream::traits_type::eof();
}

int main() {
    std::ifstream file("example.txt");
    
    if (file.is_open()) {
        if (isStreamEmpty(file)) {
            std::cout << "The file is empty." << std::endl;
        } else {
            std::cout << "The file is not empty." << std::endl;
        }
        
        file.close();
    } else {
        std::cout << "Failed to open the file." << std::endl;
    }
    
    return 0;
}