How to install and use JsonCpp library on Ubuntu Linux OS?

Learn to configure, compile and run C++ programs using JsonCpp Library

Posted by Amritpal Singh on October 09, 2017

About JsonCpp

JsonCpp is a lightweight data-interchange format. It can represent numbers, strings, ordered sequences of values, and collections of name/value pairs.

Step 1: Install using apt-get

You can easily install JsonCpp library on Ubuntu or another flavor of Debian Linux simply by running the following command:

sudo apt-get install libjsoncpp-dev

It will install the compatible JsonCpp library on your system.

Step 2: Example program and compiler flag

To compile a C++ program that uses JsonCpp library use the compiler flag:

-ljsoncpp

Create a Json file called profile.json with the following content:

{
    "firstname":"Amritpal",
    "lastname": "Singh",
    "ss": 12345678910
}

Within the same directory create a profile.cpp file with the following source code:

#include <iostream>
#include <fstream>
#include <jsoncpp/json/json.h>

using namespace std;

int main() {
    ifstream ifs("profile.json");
    Json::Reader reader;
    Json::Value obj;
    reader.parse(ifs, obj);     // Reader can also read strings
    cout << "Last name: " << obj["lastname"].asString() << endl;
    cout << "First name: " << obj["firstname"].asString() << endl;
    return 1;
}

Compile it:

g++ -o profile profile.cpp -ljsoncpp

Run it:

./profile

That's it, if you can run the profile program you have successfully configured JsonCpp library.


1 Comments

Jimmy

Nice post. Helped me get started with JSON data in c++.

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