9.30

软件构造

CSV：

 

#include <fstream>

 

#include <iostream>

 

#include <vector>

 

#include <string>

 

 

 

// 保存到CSV

 

void saveToCSV(const std::vector<std::string>& expressions, const std::string& filename) {

 

    std::ofstream file(filename.c_str());

 

    if (!file.is_open()) {

 

        std::cerr << "Unable to open file for writing: " << filename << std::endl;

 

        return;

 

    }

 

    for (std::vector<std::string>::const_iterator it = expressions.begin(); it != expressions.end(); ++it) {

 

        file << *it << std::endl;

 

    }

 

    file.close();

 

}

 

 

 

// 从CSV读取

 

std::vector<std::string> readFromCSV(const std::string& filename) {

 

    std::vector<std::string> expressions;

 

    std::ifstream file(filename.c_str());

 

    if (!file.is_open()) {

 

        std::cerr << "Unable to open file for reading: " << filename << std::endl;

 

        return expressions;

 

    }

 

    std::string line;

 

    while (std::getline(file, line)) {

 

        expressions.push_back(line);

 

    }

 

    file.close();

 

    return expressions;

 

}

 

 

 

int main() {

 

    std::vector<std::string> expressions;

 

    expressions.push_back("2 + 2=4");

 

    expressions.push_back("3 * 4=12");

 

    expressions.push_back("5 - 1=4");

 

    saveToCSV(expressions, "expressions.csv");

 

 

 

    std::vector<std::string> loadedExpressions = readFromCSV("expressions.csv");

 

    for (std::vector<std::string>::const_iterator it = loadedExpressions.begin(); it != loadedExpressions.end(); ++it) {

 

        std::cout << *it << std::endl;

 

    }

 

 

 

    return 0;

 

}