Calculate the Area of the Circle

Problem Statement: Given the radius of the circle, calculate the area of the circle.

Examples:

Example 1:
Input: N = 5
Output: 78.5
Explanation: Using formula  πr2 for finding area of circle we get area as 78.5

Example 2:
Input: N = 4
Output: 50.2
Explanation: Using formula  πr2 for finding area of circle we get area as 50.2

Solution

Disclaimer: Don’t jump directly to the solution, try it out yourself first.

Approach:

We know that the area of the circle is πr².
So taking a variable double to store decimal digits as our ans.
And multiplying pi with the square of the radius gives us the area of the circle.

Code:

C++ Code

#include <bits/stdc++.h>

using namespace std;

class Area {

  public:

    void areaOfCircle(int n) {

      double ans = 3.14 * n * n; // Area of circle = πr2
      cout << "Area of circle is : ";
      cout << ans;
    }
};
int main() {

  int n = 5;

  Area p1;
  p1.areaOfCircle(n);

  return 0;
}

Output:

Area of circle is: 78.5

Time Complexity: O(1)

Space Complexity: O(1)

Java Code

class Solution {

  public static void areaOfCircle(int n) {

    double ans = 3.14 * n * n; // Area of circle = πr2
    System.out.print("Area of circle is : " + ans);

  }
  public static void main(String args[]) {
    int n = 5;
    areaOfCircle(n);
  }
}

Output:

Area of circle is: 78.5

Time Complexity: O(1)

Space Complexity: O(1)

Special thanks to Rushikesh Adhav for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article