Sum of internal angles of a Polygon

Given an integer N, the task is to find the sum of interior angles of an N-sided polygon. A plane figure having a minimum of three sides and angles is called a polygon.
Examples:

Input: N = 3 
Output: 180 
3-sided polygon is a triangle and the sum 
of the interior angles of a triangle is 180.
Input: N = 6 
Output: 720 

Approach: The sum of internal angles of a polygon with N sides is given by (N – 2) * 180
Below is the implementation of the above approach:

C++

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;

// Function to return the sum of internal
// angles of an n-sided polygon
int sumOfInternalAngles(int n)
{
    if (n < 3)
        return 0;
    return (n - 2) * 180;
}

// Driver code
int main()
{
    int n = 5;

    cout << sumOfInternalAngles(n);

    return 0;
}

Java

// Java implementation of the approach
class GFG {

    // Function to return the sum of internal
    // angles of an n-sided polygon
    static int sumOfInternalAngles(int n)
    {
        if (n < 3)
            return 0;
        return ((n - 2) * 180);
    }

    // Driver code
    public static void main(String args[])
    {
        int n = 5;

        System.out.print(sumOfInternalAngles(n));
    }
}

C#

// C# implementation of the approach
using System;
class GFG {

    // Function to return the sum of internal
    // angles of an n-sided polygon
    static int sumOfInternalAngles(int n)
    {
        if (n < 3)
            return 0;
        return ((n - 2) * 180);
    }

    // Driver code
    public static void Main()
    {
        int n = 5;

        Console.Write(sumOfInternalAngles(n));
    }
}

Python

# Python3 implementation of the approach

# Function to return the sum of internal
# angles of an n-sided polygon
def sumOfInternalAngles(n):
    if(n < 3):
        return 0
    return ((n - 2) * 180)

# Driver code
n = 5
print(sumOfInternalAngles(n))

PHP

<?php
// PHP implementation of the approach

// Function to return the sum of internal
// angles of an n-sided polygon
function sumOfInternalAngles($n)
{
    if($n < 3)
        return 0;
    return (($n - 2) * 180);
}

// Driver code
$n = 5;
echo(sumOfInternalAngles($n));
?>

Javascript

<script>

// JavaScript implementation of the approach

// Function to return the sum of internal
// angles of an n-sided polygon
function sumOfInternalAngles(n)
{
    if (n < 3)
        return 0;
    return (n - 2) * 180;
}

// Driver code

    let n = 5;

    document.write(sumOfInternalAngles(n));


// This code is contributed by Mayank Tyagi

</script>

Output:

540

Time Complexity: O(1)

Auxiliary Space: O(1)