1.cJSON compilation and installation

• GitHub address: https://github.com/DaveGamble/cJSON
• download

git clone https://github.com/DaveGamble/cJSON.git
Compile with reference to Readme
You can directly use cjson H and cjson C add to source file

• Compile instruction

gcc test.c cJSON.c -lm

2. Data structure definition

2.1cJSON structure

/* The cJSON structure: */
typedef struct cJSON
{
	/* next/prev allow you to walk array/object chains. Alternatively, use Get ArraySize/GetArrayItem/GetObjectItem */
	struct cJSON *next;
	struct cJSON *prev;
	/* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
	struct cJSON *child;
	/* The type of the item, as above. */
	int type;
	/* The item's string, if type==cJSON_String and type == cJSON_Raw */
	char *valuestring;
	/* The item's number, if type==cJSON_Number */
	int valueint;
	/* The item's number, if type==cJSON_Number */
	double valuedouble;
12
	/* The item's name string, if this item is the child of, or is in the listof subitems of an object. */
	char *string;
} cJSON;

next and prev are used to traverse the forward and backward linked list pointers of the array or object chain; Child points to the child node of the array or object; Type is the type of value; valuestring is a string value; valueint is an integer value; valuedouble is a floating-point value; String is the name of the key.

2.2 types supported by JSON

/* cJSON Types: */
#define cJSON_Invalid (0)
#define cJSON_False (1 << 0)
#define cJSON_True (1 << 1)
#define cJSON_NULL (1 << 2)
#define cJSON_Number (1 << 3)
#define cJSON_String (1 << 4)
#define cJSON_Array (1 << 5)
#define cJSON_Object (1 << 6)
#define cJSON_Raw (1 << 7) /* raw json */

• valuestring, when the type is cJSON_String or cjson_ When raw, the value of value is NULL when the type is inconsistent
• valueint, when the type is cJSON_Number, the value of value
• valuedouble, when the type is cjson_ When number, the value of value (mainly used)
• string represents the value of the key in the key value pair

3. Key functions

3.1 cJSON_Parse

/* Supply a block of JSON, and this returns a cJSON object
you can interrogate. Call cJSON_Delete when finished. */
extern cJSON *cJSON_Parse(const char *value);

• Function: serialize a JSON string according to the structure of the cJSON structure, and open up a memory in the heap to store the cJSON structure. (string passed into c language)
• Return value: successfully returns a pointer to cJSON in the memory block, and fails to return NULL.

3.2 cJSON_Delete

/* Delete a cJSON entity and all subentities. */
extern void cJSON_Delete(cJSON *c);

• Function: release the memory of cJSON structure in the heap.
• Return value: None
• Note: when using cJSON_ After parse() obtains the cJSON pointer, if it is no longer used, you need to call cJSON_Delete() frees it, otherwise it will cause a memory leak.

3.3 cJSON_Print

/* Render a cJSON entity to text for transfer/storage.
Free the char* when finished. */
extern char *cJSON_Print(const cJSON *item);

• Function: parse cjson data into JSON strings, and open up a memory space of char * in the heap to store JSON strings. cJSON_PrintUnformatted() and cJSON_Print() is similar, except that the printout is not formatted, but just a string data.
• Return value: a char * pointer is returned successfully, which points to the JSON string in the heap, and NULL is returned in failure.
• Note: through cJSON_Print() can print all cJSON objects in the cJSON linked list, but you need to manually release the corresponding resource: free(char *).

3.4 cJSON_Version

/* returns the version of cJSON as a string */
extern const char* cJSON_Version(void);

• Function: get the version number of the currently used cJSON library.
• Return value: returns a string of data.

3.5 cJSON_GetArrayItem

/* Retrieve item number "item" from array "array".
Returns NULL if unsuccessful. */
extern cJSON *cJSON_GetArrayItem(const cJSON *array, int item);

• Function: find the cJSON object whose key is string from the cJSON chain of object.
• Return value: a pointer to the structure of cJSON type is returned successfully, and NULL is returned in failure.
• And cJSON_GetObjectItem() has the following interfaces:

/* Returns the number of items in an array (or object). */
extern int cJSON_GetArraySize(const cJSON *array);

/* Get item "string" from object. Case insensitive. */
extern cJSON *cJSON_GetObjectItem(const cJSON *object, const char *string)
;
extern int cJSON_HasObjectItem(const cJSON *object, const char *string);

4. Introduction to all functions

5. Introduction to use examples

1. Test file 1: cjson_test.c

• Compilation instruction: GCC cjson c cjson_ test. c -o cjson_ test -lm
• File content

test1() / / create a json file and parse it
test2() / / read the local json file
test3() / / add, delete, query and modify json

#include <stdio.h>
#include <stdlib.h>
#include "cJSON.h"
#include <string.h>

/**
{
	"name":	"milo",
	"age":	80,
	"professional": {major
        "english": 4,
        "putonghua": 2,
        "computer": 4
    },
    "languages":	["C++", "C"],
	"phone":	{
		"number":	"18620823143",
		"type":	"home"
	},
	"courses":	[{
			"name":	"Linux kernel development",
			"price":	"7.7"
		}, {
			"name":	"Linux server development",
			"price":	"8.0"
		}],
	"vip":	true,
	"address":	null
}
*/

//Print CJSON
void printfJson(cJSON *json) {
    if (NULL == json) {
        return;
    }
    char *cjson=cJSON_Print(json);//Deep copy
    printf("json:%s\n", cjson);
    free(cjson);
}

//release
void freeJson(cJSON *json) {
    if (json != NULL) {
        cJSON_Delete(json);
	}
}

//Create JSON
cJSON * createJson() {
    cJSON *json_root=cJSON_CreateObject();
	cJSON_AddItemToObject(json_root, "name", cJSON_CreateString("milo"));
	cJSON_AddNumberToObject(json_root, "age", 80);

    cJSON *json_professional=cJSON_CreateObject();
    cJSON_AddItemToObject(json_professional,"english", cJSON_CreateNumber(4));
    cJSON_AddItemToObject(json_professional,"putonghua", cJSON_CreateNumber(2));
    cJSON_AddItemToObject(json_professional,"computer", cJSON_CreateNumber(3));

    cJSON *json_languages=cJSON_CreateArray();
    cJSON_AddItemToArray(json_languages, cJSON_CreateString("C++"));
    cJSON_AddItemToArray(json_languages, cJSON_CreateString("C"));

    cJSON *json_phone=cJSON_CreateObject();
    cJSON_AddItemToObject(json_phone,"number", cJSON_CreateString("18620823143"));
    cJSON_AddItemToObject(json_phone,"type", cJSON_CreateString("home"));

    cJSON *json_courses = cJSON_CreateArray();
    cJSON* json_pItem1 = cJSON_CreateObject();
    cJSON_AddItemToObject(json_pItem1, "name", cJSON_CreateString("Linux kernel development"));
    cJSON_AddNumberToObject(json_pItem1, "price", 7.7);
    cJSON_AddItemToArray(json_courses, json_pItem1);

    cJSON* json_pItem2 = cJSON_CreateObject();
    cJSON_AddItemToObject(json_pItem2, "name", cJSON_CreateString("Linux server development"));
    cJSON_AddNumberToObject(json_pItem2, "price", 8.8);
    cJSON_AddItemToArray(json_courses, json_pItem2);


    cJSON_AddItemToObject(json_root, "professional", json_professional);
    cJSON_AddItemToObject(json_root, "languages", json_languages);
    cJSON_AddItemToObject(json_root, "phone", json_phone);
    cJSON_AddItemToObject(json_root, "courses", json_courses);

    cJSON_AddBoolToObject(json_root, "vip", 1);
    cJSON_AddNullToObject(json_root, "address");

    return json_root;
}

//Add to existing JSON
//"hobby": ["Basketball", "Football", "badminton"],
void addDataToJson(cJSON *json) {
    if (NULL == json) {
        return;
    }

    cJSON *hobby=cJSON_CreateArray();
    cJSON_AddItemToArray(hobby, cJSON_CreateString("Basketball"));
    cJSON_AddItemToArray(hobby, cJSON_CreateString("Football"));
    cJSON_AddItemToArray(hobby, cJSON_CreateString("badminton"));

    /*
    CJSON_PUBLIC(void) cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item);
    */
    cJSON_AddItemToObject(json, "hobby", hobby);

    printfJson(json);
}

//modify
//"hobby": ["Basketball", "Football", "badminton"],
//Change to
//"hobby": ["Skating", "dance"],
void updateDataToJson(cJSON *json) {
    if (NULL == json) {
        return;
    }

    cJSON *hobby=cJSON_CreateArray();
    cJSON_AddItemToArray(hobby, cJSON_CreateString("Skating"));
    cJSON_AddItemToArray(hobby, cJSON_CreateString("dance"));

    /*
    CJSON_PUBLIC(void) cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem);
    CJSON_PUBLIC(void) cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);
    */
    cJSON_ReplaceItemInObject(json, "hobby", hobby);

    printfJson(json);
}

//delete
//"hobby": ["Skating", "dance"],
void deleteDataToJson(cJSON *json) {
    if (NULL == json) {
        return;
    }

    /*
    CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObject(cJSON *object, const char *string);
    */
    cJSON_DetachItemFromObject(json, "hobby");

    printfJson(json);
}

//Parsing JSON
void analysisJsonObj(cJSON *json) {
    if (NULL == json) {
        return;
    }

    cJSON *json_name = cJSON_GetObjectItem(json, "name");
    printf("root[%s:%s]\n", json_name->string, json_name->valuestring);

    cJSON *json_age = cJSON_GetObjectItem(json, "age");
    printf("root[%s:%d]\n", json_age->string, json_age->valueint);

    cJSON *json_professional = cJSON_GetObjectItem(json, "professional");
    cJSON *json_professional_child = json_professional->child;
    while (json_professional_child != NULL) {
        printf("%s[%s:%d]\n", json_professional->string, json_professional_child->string, json_professional_child->valueint);
        json_professional_child = json_professional_child->next;

    }
    cJSON *json_languages = cJSON_GetObjectItem(json, "languages");
    if (json_languages) {
        int size = cJSON_GetArraySize(json_languages);
        printf("%s size:%d\n", json_languages->string, size);
        for (int i = 0; i < size; i++) {
            cJSON *json_languages_child =cJSON_GetArrayItem(json_languages, i);
            printf("%s[%d:%s]\n", json_languages->string, i, json_languages_child->valuestring);
        }
    }

    cJSON *json_phone = cJSON_GetObjectItem(json, "phone");
    cJSON *json_phone_number = cJSON_GetObjectItem(json_phone,"number");
    cJSON *json_phone_type = cJSON_GetObjectItem(json_phone,"type");
    printf("%s[%s:%s]\n", json_phone->string, json_phone_number->string, json_phone_number->valuestring);
    printf("%s[%s:%s]\n", json_phone->string, json_phone_type->string, json_phone_type->valuestring);

    cJSON *json_courses = cJSON_GetObjectItem(json, "courses");
    if (json_courses) {
        int size = cJSON_GetArraySize(json_courses);
        printf("%s size:%d\n", json_courses->string, size);
        for(int i=0;i<size;i++) {
            cJSON *json_array = cJSON_GetArrayItem(json_courses, i);
            if (json_array) {
                cJSON *json_course_name = cJSON_GetObjectItem(json_array,"name");
                cJSON *json_course_price = cJSON_GetObjectItem(json_array,"price");
                printf("%s[%s:%.1lf]\n", json_courses->string, json_course_name->string, json_course_name->valuedouble);
                printf("%s[%s:%.1lf]\n", json_courses->string, json_course_price->string, json_course_price->valuedouble);
            }
        }
    }

    cJSON *json_vip = cJSON_GetObjectItem(json, "vip");
    if (json_vip->type == cJSON_True) {
        printf("root[%s:true]\n", json_vip->string);
    } else if (json_vip->type == cJSON_False) {
        printf("root[%s:false]\n", json_vip->string);
    } else {
        printf("root[%s:false]\n", json_vip->string);
    }

    cJSON *json_address = cJSON_GetObjectItem(json, "address");
    if (json_address->type ==cJSON_NULL) {
        printf("root[%s:null]\n", json_address->string);
    }
}


static void printJsonObjvalue(const cJSON *json) {
    if (NULL == json) {
        printf("NULL object!\n");
        return;
    }

    switch (json->type) {
        case cJSON_False:
            printf("%s: false\n", json->string);
            break;
        case cJSON_True:
            printf("%s: true\n", json->string);
            break;
        case cJSON_NULL:
            printf("%s: cJSON_NULL\n", json->string);
            break;
        case cJSON_Number:
            printf("%s: %d, %f\n", json->string, json->valueint, json->valuedouble);
            break;
        case cJSON_String:
            printf("%s: %s\n", json->string, json->valuestring);
            break;
        case cJSON_Array:
            printf("%s: cJSON_Array\n", json->string);
            break;
        case cJSON_Object:
            printf("%s: cJSON_Object\n", json->string);
            break;
        default:
            printf("unknown type\n");
            break;
    }
}

void analysisJsonPrint(cJSON *json) {
    if (NULL == json) {
        return;
    }

    cJSON *json_name = cJSON_GetObjectItem(json, "name");
    printJsonObjvalue(json_name);

    cJSON *json_age = cJSON_GetObjectItem(json, "age");
    printJsonObjvalue(json_age);

    cJSON *json_professional = cJSON_GetObjectItem(json, "professional");
    cJSON *json_professional_child = json_professional->child;
    while (json_professional_child != NULL) {
        printJsonObjvalue(json_professional_child);
        json_professional_child = json_professional_child->next;
    }

    cJSON *json_languages = cJSON_GetObjectItem(json, "languages");
    if (NULL == json_languages) {
        int size = cJSON_GetArraySize(json_languages);
        printf("%s size:%d\n", json_languages->string, size);
        for (int i = 0; i < size; i++) {
            cJSON *json_languages_child = cJSON_GetArrayItem(json_languages, i);
            printJsonObjvalue(json_languages_child);
        }
    }

    cJSON *json_phone = cJSON_GetObjectItem(json, "phone");
    cJSON *json_phone_number = cJSON_GetObjectItem(json_phone,"number");
    cJSON *json_phone_type = cJSON_GetObjectItem(json_phone,"type");
    printJsonObjvalue(json_phone_number);
    printJsonObjvalue(json_phone_type);

    cJSON *json_courses = cJSON_GetObjectItem(json, "courses");
    if (json_courses) {
        int size = cJSON_GetArraySize(json_courses);
        printf("%s size:%d\n", json_courses->string, size);
        for(int i=0;i<size;i++) {
            cJSON *arrayItem = cJSON_GetArrayItem(json_courses, i);
            if (NULL != arrayItem) {
                cJSON *json_course_name = cJSON_GetObjectItem(arrayItem,"name");
                cJSON *json_course_price = cJSON_GetObjectItem(arrayItem,"price");
                printJsonObjvalue(json_course_name);
                printJsonObjvalue(json_course_price);
            }
        }
    }

    cJSON *json_vip = cJSON_GetObjectItem(json, "vip");
    printJsonObjvalue(json_vip);

    cJSON *json_address = cJSON_GetObjectItem(json, "address");
    printJsonObjvalue(json_address);
}

//Read JSON
cJSON* readJsonFile(char *fileName) {
    if (NULL == fileName) {
        return NULL;
    }

    FILE *fp = NULL;
    cJSON *json = NULL;
    char line[1024] = {0};
    char *data = NULL;

    //Open a text file. The file must exist and can only be read
    fp = fopen(fileName, "r");
    if (NULL != fp) {
        //End of seek
        fseek(fp, 0, SEEK_END);
        //Read file size
        long len = ftell(fp);
        //seek start bit value
        fseek(fp, 0, SEEK_SET);
        data = (char*)malloc(len + 1);
        fread(data, 1, len, fp);
        fclose(fp);
    }
    
    printf("readJsonFile data:%s\n", data);
    cJSON *json_root = cJSON_Parse(data);
    if (NULL == json_root) {
        printf("cJSON_Parse error:%s\n", cJSON_GetErrorPtr());
    }

    if (NULL != data) {
        free(data);
    }

    return json_root;
}

//Save JSON
void writeJsonFile(char *fileName, cJSON *json) {
    if (NULL == json || NULL == fileName) {
        return;
    }

    char *cjson=cJSON_Print(json);

    FILE *fp = NULL;
    //Create a new text file. The existing file will empty its contents and allow reading and writing
    fp = fopen(fileName, "w+");
    if (NULL != fp) {
        fwrite(cjson, strlen(cjson),1,fp);
        fclose(fp);
	}

    if (NULL != cjson) {
        free(cjson);
	}
}

void test1() {//Create a json file and parse it
    cJSON *json_root = createJson();//Create json file
    //Print
    printfJson(json_root);
    //Parsing json
    analysisJsonObj(json_root);
    //Parsing json
    analysisJsonPrint(json_root);
    freeJson(json_root);
}

void test2() {      //Read the local json file
    char *fileName = "./person.json";

    //Read json
    cJSON *json_root = readJsonFile(fileName);
    //Parsing json
    analysisJsonObj(json_root);
    //Parsing json
    analysisJsonPrint(json_root);

    //Write json file
    writeJsonFile(fileName, json_root);

    //release
    freeJson(json_root);
}

//Addition, deletion and modification
void test3() {//Add, delete, query and modify json
    cJSON *json_root = createJson();

    addDataToJson(json_root);

    updateDataToJson(json_root);

    deleteDataToJson(json_root);

    freeJson(json_root);
}

int main(int argc, char *argv[]) {
    
    // printf("-----------------------------------\n");
    // test1();
    printf("-----------------------------------\n");
    test2();
    printf("-----------------------------------\n");
    // test3();
    // printf("-----------------------------------\n");

    return 0;
}

JSON file: person json

{
	"name":	"milo",
	"age":	80,
	"professional":	{
		"english":	4,
		"putonghua":	2,
		"computer":	3
	},
	"languages":	["C++", "C"],
	"phone":	{
		"number":	"18620823143",
		"type":	"home"
	},
	"courses":	[{
			"name":	"Linux kernel development",
			"price":	7.700000
		}, {
			"name":	"Linux server development",
			"price":	8.800000
		}],
	"vip":	true,
	"address":	null
}

2. Test file 2: comment_test.c

• Compilation instruction: GCC cjson c comment_ test. c -o comment_ test -lm
• File content

test1() / / convert the comment structure to json format
test2() / / read the local json file

code:

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include "cJSON.h"
#include <string.h>


//comment
typedef struct COMMENT
{
    int user_id;
    int msg_id;
    char* comment;
    int click_count;
    int like_count;
    int reply_count;
    int is_new_reply;
    long add_time;
} COMMENT;

//Gets the current time in milliseconds
long getCurrentTime()
{
    struct timeval tv;
    gettimeofday(&tv,NULL);
    //millisecond
    long time_sec = tv.tv_sec*1000 + tv.tv_usec/1000;

    return time_sec;
}

//Print CJSON
void printfJson(cJSON *json) {
    if (NULL == json) {
        return;
    }
    char *cjson=cJSON_Print(json);//Deep copy
    printf("json:%s\n", cjson);
    free(cjson);
}

void freeComment(COMMENT *comment) {
    if (comment != NULL) {
        if (comment->comment != NULL) {
            free(comment->comment);
            comment->comment = NULL;
        }

        free(comment);
        comment = NULL;
    }
}

void freeJson(cJSON *json) {
    if (json != NULL) {
        cJSON_Delete(json);
	}
}

/**
json object
{
    "user_id":1,
    "msg_id":1,
    "comment":"json",
    "click_count":0,
    "like_count":0,
    "reply_count":0,
    "is_new_reply":0,
    "add_time":0,
}
*/

//After passing the comment, create the json class
//Convert structure to cJSON
cJSON *convertToJson(COMMENT *comment) 
{
    if (comment == NULL) {
        return NULL;
    }

    //Build json
    //char *cjson = "{\"name\":\"milo\"}";// To build json in this way, you need to use cJSON_Parse() is constructed by this method to parse the string into a cJSON structure
    //cJSON *json = cJSON_Parse(cjson);// The JSON created in this way has data

    //Create json
    //Convert the structure into json protocol, save or provide it to the client
    cJSON *json=cJSON_CreateObject();//The json created in this way has no data
    //Add "user_id" to the "json" node 
	cJSON_AddNumberToObject(json, "user_id", comment->user_id);//AddNumber means that the corresponding type is a number type, and the number type includes integer and floating point
	cJSON_AddNumberToObject(json, "msg_id", comment->msg_id);

    cJSON_AddItemToObject(json, "comment", cJSON_CreateString(comment->comment));//Here, the structure data is converted to json
    cJSON_AddNumberToObject(json, "click_count", comment->click_count);
    cJSON_AddNumberToObject(json, "like_count", comment->like_count);
    cJSON_AddNumberToObject(json, "reply_count", comment->reply_count);
    cJSON_AddNumberToObject(json, "is_new_reply", comment->is_new_reply);
    cJSON_AddNumberToObject(json, "add_time", comment->add_time);

    return json;
}

//Assign cJSON to structure
//For example, here is the json format that the client gets from the server
COMMENT* convertToComment(cJSON *json)
{  
    if (NULL == json) {
        return NULL;
    }
   
    cJSON *json_user_id = cJSON_GetObjectItem(json, "user_id");
    cJSON *json_msg_id = cJSON_GetObjectItem(json, "msg_id");
    cJSON *json_comment = cJSON_GetObjectItem(json, "comment");
    cJSON *json_click_count = cJSON_GetObjectItem(json, "click_count");
    cJSON *json_like_count = cJSON_GetObjectItem(json, "like_count");
    cJSON *json_reply_count = cJSON_GetObjectItem(json, "reply_count");
    cJSON *json_is_new_reply = cJSON_GetObjectItem(json, "is_new_reply");
    cJSON *json_add_time = cJSON_GetObjectItem(json, "add_time");

    COMMENT *comment = (COMMENT *)malloc(sizeof(COMMENT));
    comment->user_id = json_user_id->valueint;
    comment->msg_id = json_msg_id->valueint;
    comment->comment=(char *)malloc(256);
    memset(comment->comment, 0, 256);
    strcat(comment->comment, json_comment->valuestring);
    comment->click_count = json_click_count->valueint;
    comment->like_count = json_like_count->valueint;
    comment->reply_count = json_reply_count->valueint;
    comment->is_new_reply = json_is_new_reply->valueint;
    comment->add_time = (long)(json_add_time->valuedouble);

    return comment;
}

//Read json from file
void readJsonFromData(char *data) {
    cJSON *json=cJSON_Parse(data);              //Build data into cJSON structure
    //Print json
    printfJson(json);                           //Print json   

    COMMENT* comment = convertToComment(json);  //It is similar to unpacking json packages. For example, here is the json format that the client gets from the server
    if (comment != NULL) {
        
        comment->like_count = 77;               //
        comment->reply_count = 99;              //

        //Convert to json
        cJSON *childjson = convertToJson(comment);
        //Print json
        printfJson(childjson);
        //Release object
        freeComment(comment);
        //
        freeJson(childjson);
	}
    freeJson(json);
}

//Save JSON
void writeJsonFile(cJSON *json) {
    if (NULL == json) {
        return;
    }

    char *cjson=cJSON_Print(json);

    FILE *fp = NULL;
    char *fileName = "./comment.json";
    fp = fopen(fileName, "w+");
    if (NULL != fp) {
        fwrite(cjson, strlen(cjson),1,fp);
        fclose(fp);
	}
    if (cjson != NULL) {
        free(cjson);
	}
}

//Read JSON
void readJsonFile() {
    FILE *fp = NULL;
    char *out;
    char line[1024] = {0};
    char *fileName = "./comment.json";

    //Open a text file. The file must exist and can only be read
    fp = fopen(fileName, "r");
    //End of seek
    fseek(fp, 0, SEEK_END);
    //Read file size
    long len = ftell(fp);
    //seek start bit value
    fseek(fp, 0, SEEK_SET);
    char *data = (char*)malloc(len + 1);
    fread(data, 1, len, fp);
    if (fp != NULL) {
        fclose(fp);
	}

    //read
    readJsonFromData(data);
    
    if (NULL != data) {
        free(data);
    }
}

//Got a comment object
COMMENT *createComment() {
    COMMENT *comment = (COMMENT *)malloc(sizeof(COMMENT));
    comment->user_id = 1;
    comment->msg_id = 10000;
    comment->comment=(char *)malloc(256);
    memset(comment->comment, 0, 256);
    sprintf(comment->comment, "I agree with you");
    comment->click_count = 0;
    comment->like_count = 0;
    comment->reply_count = 0;
    comment->is_new_reply = 0;
    comment->add_time = getCurrentTime();
    return comment;
}

void test1() {
    COMMENT *comment = createComment();//To create a comment object is to initialize the packet structure

    //Convert to json
    cJSON *json = convertToJson(comment);//Convert the structure to cJSON and return the json object
    
    //Save json
    writeJsonFile(json);//Save json locally

    freeComment(comment);//Release structure data

    freeJson(json);//
}

void test2() {
    //Read json
    readJsonFile();
}

int main(int argc, char *argv[]) {
    
    test1();

    test2();

    return 0;
}

JSON file: comment json

{
	"user_id":	1,
	"msg_id":	10000,
	"comment":	"I agree with you",
	"click_count":	0,
	"like_count":	0,
	"reply_count":	0,
	"is_new_reply":	0,
	"add_time":	1624628790079
}