JavaScript/Primitive data types/Exercises

Topic: Primitive Data Types

1. Write a script with the following steps (the 'power'-operator is '**'):

Compute the value of 2⁵⁰. Store it in the variable x1.
Compute the value of 2⁵⁰ + 1. Store it in the variable x2.
Compare x1 with x2. Are they equal?

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"use strict";constx1=2**50;constx2=2**50+1;alert(x1==x2);// false

2. Repeat the previous exercise with 2⁶⁰ instead of 2⁵⁰.

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"use strict";constx1=2**60;constx2=2**60+1;alert(x1==x2);// true

3. Repeat the previous exercise with 1000 instead of 1.

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"use strict";constx1=2**60;constx2=2**60+1000;alert(x1==x2);// false

4. Discuss the results of exercises 1 - 3 with your colleague.

5. Write a script with the following steps:

Compute the value of one divided by three. Store the result in the variable x1.
Show x1.
Multiply x1 by three and store the result in x2.
Show x2. Which value do you expect?

Click to see solution

"use strict";constx1=1/3;alert(x1);constx2=x1*3;alert(x2);

6. Write a script that shows that 5 and 5.0 are identical values.

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"use strict";constx1=5;constx2=5.0;alert(x1==x2);

7. Write a script that

asks the user how old he is: prompt(...)
prompt() always returns a string. To perform the calculation, it's necessary to convert the answer to number parseInt(), parseFloat(), Number()
if his answer is a numeric value, show how often his heart has beaten since his birth (approximately once per second)
else, give a message like "Sorry. We need a numeric value to perform the computation."

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// a possible solution:"use strict";constanswer=prompt("How old are you?");// returns a stringconstage=parseFloat(answer);// what's about parseInt() or Number() ?if(Number.isNaN(age)){// try other solutions!alert("Sorry, we need a number to perform the calculation. You typed: '"+answer+"'");}else{// about one beat per secondconstseconds=age*365*24*60*60;alert("Your heart has beaten (approximately) "+seconds+" times since your birth.");}

8. Create a HTML page for the previous exercise and embed the solution into the HTML. You can refer to this example.

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<!DOCTYPE html><html><head><title>Seconds</title><script>functiongo(){"use strict";letresult;constanswer=document.getElementById("age").value;constage=Number(answer);if(Number.isNaN(age)){// try other solutions!result="Sorry, we need a number to perform the calculation. You typed: '"+answer+"'";}else{// about one beat per secondconstseconds=age*365*24*60*60;result="Your heart has beaten (approximately) "+seconds+" times since your birth.";}document.getElementById("result").innerText=result;}</script></head><body><h1>How many times has your heart beaten?</h1><label>Your age: </label><inputtype="text"id="age"><buttontype="button"onclick="go()">GO</button><p><divid="result">???</div></p></body></html>