c++如何删除/替换文件的最后一行？

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

int main() {
    std::string filePath = "example.txt";
    std::ifstream file(filePath);
    std::vector<std::string> lines;
    std::string line;

    if (file.is_open()) {
        while (getline(file, line)) {
            lines.push_back(line);
        }
        file.close();
    } else {
        std::cerr << "Unable to open file\n";
        return 1;
    }

    // 检查是否至少有一行
    if (!lines.empty()) {
        lines.pop_back();  // 删除最后一行
    }

    // 重新写入文件，不包括最后一行
    std::ofstream outFile(filePath);
    if (outFile.is_open()) {
        for (const auto& l : lines) {
            outFile << l << "\n";
        }
        outFile.close();
    } else {
        std::cerr << "Unable to open file for writing\n";
        return 1;
    }

    return 0;
}

if (!lines.empty()) {
    lines.back() = "This is the new last line";  // 替换最后一行
}