nlohmann可以自动兼容将C++的很多原生类型转换为json，甚至自定义类型也不需要太复杂的操作就可以转换为json，可以利用这一点将数据转换为string：

#include <nlohmann/json.hpp>
#include <string>
#include <vector>
#include <tuple>
#include <iostream>
#include <concepts>
using namespace std;
using json = nlohmann::json;template<typename T>
concept TO_JSONSTR = requires(T t)
{json(t);
};template<TO_JSONSTR T>
string toStr(T t)
{json j = t;return j.dump();
}template<class T>
string toStr(T t)
{cout<<"can't convert to string";return "";
}struct Person1{string name = "xiaoming";int sex = 1;
};NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT(Person1, name, sex)struct Person2{string name = "xiaoming";int sex = 1;
};int main()
{int a1 = 1;auto s1 = toStr(a1);cout<<s1<<endl;