variable-let-const.js

// var a = "Hello World";
// var a=30; //over write a value
// console.log(a);

//define variable

//var firstName = "Helloo world";
//var 88firstName = "Helloo world"; // this is worng way
//var first-name = "Helloo world"; // this is worng way
// var first_name = "Helloo world";
// var firstname = "Helloo world";

// var a , b; //this is undinfe
// a = 10;
// b=20;
// console.log(a);
// console.log(b);

//LET

// let firstname = "Helloo world";
// firstname = "Helloo world 90"; //let not deifne same variable and dinfne single time variable and use multiple time defrant value
// console.log(firstname);

//CONST

// const firstname = "Helloo world";
// //firstname = "Helloo world 90"; //const not deifne same variable and not a single time dinfine and use only single time
// console.log(firstname);

// //Defrant Var, Const, Let

// // Var:- var define multiple time override a value it working and print a letest value
// // exm: var a="helloo";
// //      var a="Hii";
// //      a="123"; 

// // Let: Let deifne a single time variable if you define a same varible multiple time that is thow a error but varible value do over ride
// // exm: let a="helo";
// //         a="123";

// Const: Const define a sinle vaible and value and not allowed override value and same variable not define 
// exm: const a="helloo";
//         a="hiii"; //thow error so run only signle query