# Number of quadrilateral formed with N distinct points on circumference of Circle

Given an integer N which denotes the points on the circumference of a circle, the task is to find the number of quadrilaterals formed using these points.

Examples:

Input: N = 5
Output: 5

Input: N = 10
Output: 210

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to use permutation and combination to find the number of possible quadrilaterals using the N points on the circumference of the circle. The number of possible quadrilaterals will be .

Below is the implementation of the above approach:

## C++

 `// C++ implementation to find the  ` `// number of quadrilaterals formed ` `// with N distinct points ` `#include ` `using` `namespace` `std; ` ` `  `// Function to find the factorial ` `// of the given number N ` `int` `fact(``int` `n) ` `{ ` `    ``int` `res = 1; ` ` `  `    ``// Loop to find the factorial ` `    ``// of the given number ` `    ``for``(``int` `i = 2; i < n + 1; i++) ` `       ``res = res * i; ` `        `  `    ``return` `res; ` `} ` ` `  `// Function to find the number of ` `// combinations in the N ` `int` `nCr(``int` `n, ``int` `r)  ` `{ ` `    ``return` `(fact(n) / (fact(r) *  ` `                       ``fact(n - r))); ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``int` `n = 5; ` ` `  `    ``// Function Call ` `    ``cout << (nCr(n, 4)); ` `} ` ` `  `// This code is contributed by rock_cool `

## Java

 `// Java implementation to find the  ` `// number of quadrilaterals formed ` `// with N distinct points ` `class` `GFG{ ` `     `  `// Function to find the number of ` `// combinations in the N ` `static` `int` `nCr(``int` `n, ``int` `r)  ` `{ ` `    ``return` `(fact(n) / (fact(r) *  ` `                       ``fact(n - r))); ` `} ` ` `  `// Function to find the factorial ` `// of the given number N ` `static` `int` `fact(``int` `n) ` `{ ` `    ``int` `res = ``1``; ` ` `  `    ``// Loop to find the factorial ` `    ``// of the given number ` `    ``for``(``int` `i = ``2``; i < n + ``1``; i++) ` `        ``res = res * i; ` `    ``return` `res; ` `} ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `n = ``5``; ` ` `  `    ``// Function Call ` `    ``System.out.println(nCr(n, ``4``)); ` `} ` `} ` ` `  `// This code is contributed by 29AjayKumar `

## Python3

 `# Python3 implementation to find the  ` `# number of quadrilaterals formed ` `# with N distinct points ` ` `  `# Function to find the number of  ` `# combinations in the N ` `def` `nCr(n, r):  ` `    ``return` `(fact(n) ``/` `(fact(r)  ` `                ``*` `fact(n ``-` `r)))  ` ` `  `# Function to find the factorial  ` `# of the given number N ` `def` `fact(n):  ` `    ``res ``=` `1` `     `  `    ``# Loop to find the factorial  ` `    ``# of the given number ` `    ``for` `i ``in` `range``(``2``, n ``+` `1``): ` `        ``res ``=` `res ``*` `i      ` `    ``return` `res  ` ` `  `# Driver Code ` `if` `__name__ ``=``=` `"__main__"``: ` `    ``n ``=` `5` `     `  `    ``# Function Call ` `    ``print``(``int``(nCr(n, ``4``))) `

## C#

 `// C# implementation to find the  ` `// number of quadrilaterals formed ` `// with N distinct points ` `using` `System; ` `class` `GFG{ ` `     `  `// Function to find the number of ` `// combinations in the N ` `static` `int` `nCr(``int` `n, ``int` `r)  ` `{ ` `    ``return` `(fact(n) / (fact(r) *  ` `                       ``fact(n - r))); ` `} ` ` `  `// Function to find the factorial ` `// of the given number N ` `static` `int` `fact(``int` `n) ` `{ ` `    ``int` `res = 1; ` ` `  `    ``// Loop to find the factorial ` `    ``// of the given number ` `    ``for``(``int` `i = 2; i < n + 1; i++) ` `        ``res = res * i; ` `    ``return` `res; ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``int` `n = 5; ` ` `  `    ``// Function Call ` `    ``Console.Write(nCr(n, 4)); ` `} ` `} ` ` `  `// This code is contributed by shivanisinghss2110 `

Output:

```5
```

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