编写了一个可以读入文本并输出文本有多少字符的程序

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

int countCharacters(const std::string& filename) {
    std::ifstream file(filename);
    if (!file) {
        std::cerr << "无法打开文件: " << filename << std::endl;
        return -1;
    }

    int count = 0;
    std::string line;
    while (std::getline(file, line)) {
        count += line.length();
    }

    return count;
}

int main() {
    std::string filename;
    std::cout << "请输入文件名: ";
    std::cin >> filename;

    int count = countCharacters(filename);
    if (count >= 0) {
        std::cout << "字符数: " << count << std::endl;
    }

    return 0;
}