/Calculator-Javascript

Primary LanguageJavaScript

Questions and Answers about Variables and Operators

Question 1: What's a variable?

Answer: A variable is a container for a value, which can be of various types.

Question 2: What's a constant?

Answer: A constant is a container for a value, which can be of various types, but once set, it cannot be changed.

Question 3: In the following code, what is the variable and what is the data of the variable?

let userAge = 30;

Answer: The variable is userAge and the data of the variable is 30.

Question 4 : Could you replace this snippet ?

                 let age = 30;
                 alert(age);

             with this one

                 alert(30);

Answer: Yes. age is a variable that stores 30 as a value. Whenever you refer to the variable, you could also directly use the value (without storing it in a variable) first.

Question 5 : Why do we need variables if

                 let age = 30;
                 alert(age);

             can be re-written as ?

                 alert(30);

Answer: Variables are used to store values that can be used later in the code. They are used to store values that can be used multiple times in the code. They are also used to store values that can be changed later in the code. They are used to store values that are calculated based on other values

Question 6 : Which kind of operator is the = operator?

Answer: The = operator is an assignment operator.

Questions and Answers about Variables and Operators

Question 1 : Where do "data types" come into play ?

Answer: Data you work with in your code is of different type -e.g. numbers,text etc...

Question 2 : Which of the followwing statements correctly creates a number and stores it in a constant ?

const userAge = '30';
const userAge = let 30;
const userAge = 30;

Answer: This is correct :

const userAge = 30;

Question 3 : Is 30 the same as '30' ?

Answer: No.

Question 4 : Which of the following snippets will NOT yield an error ?

let myOtherName;
const myName = 'Max';
myName='Max';
alert(myName);
let myOtherName;
const myName = 'Max';
myOtherName='Max';
alert(myName);
let myOtherName;
const myName = 'Max';
myName=30;
alert(myName);

Answer: This is correct :

let myOtherName;
const myName = 'Max';
myOtherName='Max';
alert(myName);

Question 5 : Givent that JavaScript is a weakly typed, dynamic language, would you expect that this code works ?

let myName = 'Max';
myName = 30;

Answer: This code snippet will work. Variables in JavaScript are NOT tied to data types.