下面代码69-72行一共插入了4次，可是在结果里面只是插入了一次

Question

下面代码69-72行一共插入了4次，可是在结果里面只是插入了一次

//这是申明
bool insertjsonsample(const string& id,const string& pid);


111 bool insert2json(json& jstarget, const json& jssrc) {
112 
113     //for (json::iterator it = jssrc.begin(); it!=jssrc.end(); ++it){
114     //for (json::iterator it = object1.begin(); it!=object1.end(); ++it){
115 
116     for (auto it = jssrc.begin(); it!=jssrc.end(); ++it){
117         string key = it.key();
118         json value = it.value();
119     cout << "begin to merge json" << endl;
120 
121     //for (auto& [key, value] : object1.items()){
122         jstarget[key]=value;
123         //jstarget["key"]=value;
124     }
125     return true;
126 
127 }



int main(){
......
59     json object1 = R"({"ProjName":"*********************hn","FileName":"eeee.catpart", "ProjNumber":30, "JpgFile":"kk.jpg","Comments": "cdr     for employee","ProjType": "graphic design","ProjState": 1,  "version": 1,"CreateTime": "20230728","UpdateTime": "20230608","id": 8, "pid": 6    })"_json;
 60     /*cout << "begin to merge json" << endl;
 61     for (json::iterator it = object1.begin(); it!=object1.end(); ++it){
 62         auto& key = it.key();
 63         auto& value = it.value();
 64     cout << "begin to merge json" << endl;
 65         
 66     //for (auto& [key, value] : object1.items()){
 67         j[key]=value;
 68     }*/
 69     insert2json(j, object1);
 70     insert2json(j, object1);
 71     insert2json(j, object1);
 72     insert2json(j, object1);
 73     out << setw(4) << j.dump();

Answer 1

让阿豪来帮你解答，本回答参考chatgpt3.5编写提供，如需一对一服务私聊我哦

该代码中的 insert2json 函数只是简单地将 jssrc 中的每个键值对插入到 jstarget 中，由于 json 的 key 必须唯一，所以在插入相同的键值对时只会保留最后一个。因此，在该代码中插入了四次，但仅保留了最后一次插入的键值对。 示例代码：

#include <iostream>
#include <iomanip>
#include <string>
#include "json.hpp"
using json = nlohmann::json;
bool insert2json(json& jstarget, const json& jssrc) {
    for (auto it = jssrc.begin(); it != jssrc.end(); ++it) {
        std::string key = it.key();
        json value = it.value();
        jstarget[key] = value;
    }
    return true;
}
int main() {
    json j;
    json object1 = R"({"ProjName":"*********************hn","FileName":"eeee.catpart","ProjNumber":30,"JpgFile":"kk.jpg","Comments":"cdr for employee","ProjType":"graphic design","ProjState":1,"version":1,"CreateTime":"20230728","UpdateTime":"20230608","id":8,"pid":6})"_json;
    insert2json(j, object1);
    insert2json(j, object1);
    insert2json(j, object1);
    insert2json(j, object1);
    std::cout << std::setw(4) << j.dump() << std::endl;
    return 0;
}