jsoncpp 使用

// json.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <string>
#include <iostream>
#include <fstream>
#include <ctime>			// for time
#include <cstdlib>			// for rand srand
using namespace std;

#include <windows.h>		// for tickcount64

#include "json/json.h"

/**@brief low letter*/
static const char* sLetters = "abcdefghijklmnopqrstuvwxyz";
/**@brief low letter length*/
static const int sLen = strlen(sLetters);

/**
*	describe generate random string for test
*	param{lenth} size of string to generation
*	return a random string
*/
string getRandomString(int lenth)
{
string s(lenth, ' ');
srand(time(0));
for(int i=0; i<lenth; ++i)
{
s += sLetters[rand()%sLen];
}
return s;
}

/**
*	describe save json to local file
*	param{fn} file name to save
*	return void
*/
static void SaveToFile(const char* fn)
{
int i = 0;
int j = 0;
Json::Value root;	// json root
// dd_type, root member keys, which can be got by Value::members function ,
// you can use Value::isMember to test whether a key is belong to the Value
static const char* dd_type[] = { "online", "local", "favorite", NULL};
srand(time(0));
while (dd_type[j])
{
Json::Value items(Json::arrayValue);	// json array type
int cnt = rand()%20 + 100;
for (int k=0; k<cnt; ++k)
{
Json::Value item;
item["id"] = i++;
item["url"] = getRandomString(rand()%10 + 5) + ".com";
item["read"] = i%2;
items.append(item);
}
root[dd_type[j++]] = items;
}
{
ofstream out(fn, ofstream::out | ofstream::binary);
if (out.is_open())
{
out << root;
out.close();
}
}
}

int _tmain(int argc, _TCHAR* argv[])
{
LONG64 s = GetTickCount64();
SaveToFile("out.json");
cout << "OK, time elapsed: " << GetTickCount64() - s << " ms";
getchar();
return 0;
}