Creating a json database with user input - c++

Question

I need to create my .json array to look like this:
{
"airports": [{
"address": "Horley, Gatwick RH6 0NP, UK",
"city": "London",
"shortVersion": "LGW"
},
{
"address": "Marupe, LV-1053",
"city": "Riga",
"shortVersion": "RIX"
}
]
}
But I have it looking right now like this:
{
"airports": {
"(LGW)": {
"address": "Horley, Gatwick RH6 0NP, UK",
"city": "London",
"shortVersion": "(LGW)"
},
"(RIX)": {
"address": "Marupe, LV-1053",
"city": "Riga",
"shortVersion": "(RIX)"
}
}
}
The code I have for user input right now is this:
airports["airports"][inputShortVersion]["shortVersion"] = inputShortVersion;
airports["airports"][inputShortVersion]["city"] = inputCity;
airports["airports"][inputShortVersion]["address"] = inputAddress;
I've searched for a whole day on how to do this, but closest I got to was where it does create the above array but after input it overwrites the last airport data.
I'm using nlohmann json library.

Answer 1

You have a sequence container in your desired output, but associative container in your code.
Try something like
json inputAirport;
inputAirport["shortVersion"] = inputShortVersion;
inputAirport["city"] = inputCity;
inputAirport["address"] = inputAddress;
airports["airports"].push_back(inputAirport);

Answer 2

Apparently, you are creating a json object instead of a json array. To get an array, you could try along the lines of the following:
airports["airports"] = nlohmann::json::array()
new_airport = nlohmann::json::object()
new_airport["shortVersion"] = inputShortVersion;
new_airport["city"] = inputCity;
new_airport["address"] = inputAddress;
airports["airports"].emplace_back(new_airport);
This can be written shorter with braced initalizer lists at the cost of readability:
airports["airports"] = nlohmann::json::array()
airports["airports"].emplace_back(
{
{"shortVersion", inputShortVersion},
{"city", inputCity},
{"address", inputAddress}
});