C++实现多个map结构内容序列化写入文件

题目描述

C++实现多个map结构内容序列化写入文件

代码
```javascript
#include <map>
#include <string.h>
#include <iostream>
#include <stdio.h>
#include <fstream>
#include <istream>
#include <unistd.h>
#include <cstdlib>
int WriteFile(std::string fname, std::map<std::string, std::string> *m)
{
    int count = 0;
    if (m->empty())
        return 0;

    FILE *fp = fopen(fname.c_str(), "w");
    if (!fp)
        return -errno;

    for (std::map<std::string, std::string>::iterator it = m->begin(); it != m->end(); it++)
    {
        fprintf(fp, "%s=%s\n", it->first.c_str(), it->second.c_str());
        count++;
    }

    fclose(fp);
    return count;
}

int ReadFile(std::string fname, std::map<std::string, std::string> *m)
{
    int count = 0;
    if (access(fname.c_str(), R_OK) < 0)
        return -errno;

    FILE *fp = fopen(fname.c_str(), "r");
    if (!fp)
        return -errno;

    m->clear();

    char *buf = 0;
    size_t buflen = 0;

    while (getline(&buf, &buflen, fp) > 0)
    {
        char *nl = strchr(buf, '\n');
        if (nl == NULL)
            continue;
        *nl = 0;

        char *sep = strchr(buf, '=');
        if (sep == NULL)
            continue;
        *sep = 0;
        sep++;

        std::string s1 = buf;
        std::string s2 = sep;

        (*m)[s1] = s2;

        count++;
    }

    if (buf)
        free(buf);

    fclose(fp);
    return count;
}

int main()
{
    std::string filename = "1.txt";
    std::map<std::string, std::string> map1;
    std::map<std::string, std::string> map2;
    map1.insert(std::pair<std::string, std::string>("A", "20"));
    map1.insert(std::pair<std::string, std::string>("B", "22"));
    map1.insert(std::pair<std::string, std::string>("C", "21"));
    WriteFile(filename, &map1)
        ReadFile(filename, &map2);
    for (auto it = map2.begin(); it != map2.end(); ++it)
    {
        cout << "key:" << it->first << " value:" << it->second << endl;
    }
    return 0;
}