Day1 Let and Const

Day1 Let and Const

Objective

In this challenge, we practice declaring variables using the let and const keywords. Check out the attached tutorial for more details.


Task

  1. Declare a constant variable, PI, and assign it the value Math.PI. You will not pass this challenge unless the variable is declared as a constant and named PI (uppercase).
  2. Read a number, r, denoting the radius of a circle from stdin.
  3. Use PI and r to calculate the area and perimeter of a circle having radius r.
  4. Print area as the first line of output and print perimeter as the second line of output.

Input Format

A single integer, r, denoting the radius of a circle.


Constraints

  • 0 <= r <= 100
  • r is a floating-point number scaled to at most 3 decimal places.

Output Format

Print the following two lines:

  1. On the first line, print the area of the circle having radius r.
  2. On the second line, print the perimeter of the circle having radius r.

Sample Input 0

1
2.6

Sample Output 0

1
2
21.237166338267002
16.336281798666924

Explanation

Given the radius r = 2.6, we calculate the following:

We then print area as our first line of output and perimeter as our second line of output.



Solution

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function main() {
let r = parseFloat(readLine());
let PI = Math.PI;

console.log(PI * r * r);
console.log(PI * 2 * r);

try {
PI = 0;
console.log(PI);
} catch(error) {
console.error("You correctly declared 'PI' as a constant.");
}
}

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