output file

{
  "class": {
    "student": [
      {
        "firstname": "dinkar",
        "nickname": "dinkar",
        "marks": "85"
      },
      {
        "-rollno": "493",
        "firstname": "Vaneet",
        "lastname": "Gupta",
        "nickname": "vinni",
        "marks": "95"
      },
      {
        "-rollno": "593",
        "firstname": "jasvir",
        "lastname": "singn",
        "nickname": "jazz",
        "marks": "90"
      }
    ]
  }
}