访问json文件中的嵌套结构 [英] Access nested struct in json file
问题描述
我正在使用 frozen.h 获取json文件..我想将 .json文件中的书籍数组信息读入结构数组
*********** 问题1 **********
.. struct book有一个嵌套的struct日期，我想在.json文件中访问..但是库不会允许我..如果你知道我的解决方案freeze.h的问题或者你建议在C中使用另一个支持以下功能的json文件库：
*读/写json文件和嵌套结构的结构数组
*将字符串直接扫描到C变量中
*将C变量直接打印到输出流中
*修改现有的JSON字符串
********* 问题2 **********
将书名存储在数组[0] .title中时，例如保存的字符串是自动化而不是自动化和机器人
我尝试过：
i am using frozen.h for json files .. I want to read the book array info from .json file into an array of structs
***********problem 1**********
.. struct book has a nested struct date which I want to access in .json file .. but the library won't allow me .. if you know a solution to my problem with frozen.h OR you'd recommend another library for json files in C that supports the following feature:
* read/write from/into json file and array of structs that has nested structs
*scans a string directly into C variables
* prints C variables directly into an output stream
* modifies an existing JSON string
*********problem 2**********
when storing the book title in array[0].title for example the saved string is Automation only not Automation and Robotics
What I have tried:
#include <stdio.h>
#include "frozen.h"
#include <stdlib.h>
#include <string.h>
typedef struct
{
int day;
int month;
int year;
} dateStruct;
typedef struct
{
char title[10];
char author[10];
char publisher[10];
char ISBN[10];
dateStruct date;
int copies;
int current;
int times_borrowed;
} book;
int main()
{ book array[3];
char *content = json_fread("tmp.json");
//tmp.json exists near main.c
//and written in json format
int i, value, len = strlen(content);
struct json_token t;
for (i = 0; json_scanf_array_elem(content, len, ".book", i, &t) > 0; i++) {
json_scanf(t.ptr, t.len, "{title: %s}", &(ar[i].title));
printf("%s\n\n",array[i].title);
}
return 0;
}
========== json file ============
==========the json file ============
{
预订：[
{
title：Automation and Robotics，
作者：Miltiadis Boboulos，
出版者：学术研究出版社，
ISBN：978-87-7681- 696-4，
日期：[
{
day：14
月：12
年：2017
}]，
副本：5
当前：3
}，
{
title：engineering，
author：Abimbola Windapo，
publisher： Allen& Unwin，
ISBN：978-87-403-0362-9，
日期：[
{
day：14
month：12
年：2017
}]，
副本：7
当前：6
}
]
}
{
"book": [
{
"title": "Automation And Robotics",
"author": "Miltiadis Boboulos",
"publisher": "Academic Studies Press",
"ISBN": "978-87-7681-696-4",
"date" : [
{
"day":14
"month":12
"year":2017
} ],
"copies":5
"current":3
},
{
"title": "engineering",
"author": "Abimbola Windapo",
"publisher": "Allen & Unwin",
"ISBN": "978-87-403-0362-9",
"date" : [
{
"day":14
"month":12
"year":2017
} ],
"copies":7
"current":6
}
]
}
推荐答案
你没有以正确的方式使用该库。请查看 Github上的示例代码以了解它。关键功能是json_scanf，它可以有不同的参数，如扫描子对象的函数指针。其余的是代码嵌套以匹配您的数据结构。
you arent using the library in the correct way. Take a look at the sample code on Github to understand it. The key fuction is json_scanf which can have different parameter like a function pointer to scan subobjects. The rest is some nesting of the code to match your data structure.
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