# Number of triangles in a plane if no more than two points are collinear

Given n points in a plane and no more than two points are collinear, the task is to count the number of triangles in a given plane.**Examples:**

Input : n = 3 Output : 1 Input : n = 4 Output : 4

Let there are n points in a plane and no three or more points are collinear then number of triangles in the given plane is given by

## C++

`// C++ program to find the number of` `// triangles in a plane if no more` `// then two points are collinear.` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Function to find number of triangles` `// in a plane.` `int` `countNumberOfTriangles(` `int` `n)` `{` ` ` `// Formula to find number of triangles` ` ` `// nC3 = n * (n - 1) * (n - 2) / 6` ` ` `return` `n * (n - 1) * (n - 2) / 6;` `}` `// Driver code` `int` `main()` `{` ` ` `int` `n = 4;` ` ` `cout << countNumberOfTriangles(n);` ` ` `return` `0;` `}` |

## Java

`// Java program to find the number of` `// triangles in a plane if no more` `// then two points are collinear.` `import` `java.io.*;` `class` `GFG {` ` ` `// Function to find number of triangles` ` ` `// in a plane.` ` ` `static` `int` `countNumberOfTriangles(` `int` `n)` ` ` `{` ` ` `// Formula to find number of triangle` ` ` `// nC3 = n * (n - 1) * (n - 2) / 6` ` ` `return` `n * (n - ` `1` `) * (n - ` `2` `) / ` `6` `;` ` ` `}` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `n = ` `4` `;` ` ` `System.out.println(` ` ` `countNumberOfTriangles(n));` ` ` `}` `}` |

## Python3

`# Python3 program to find` `# the number of triangles` `# in a plane if no more` `# then two points are collinear.` `# Function to find number` `# of triangles in a plane.` `def` `countNumberOfTriangles(n) :` ` ` ` ` `# Formula to find` ` ` `# number of triangles` ` ` `# nC3 = n * (n - 1) *` ` ` `# (n - 2) / 6` ` ` `return` `(n ` `*` `(n ` `-` `1` `) ` `*` ` ` `(n ` `-` `2` `) ` `/` `/` `6` `)` `# Driver Code` `if` `__name__ ` `=` `=` `'__main__'` `:` ` ` ` ` `n ` `=` `4` ` ` `print` `(countNumberOfTriangles(n))` ` ` `# This code is contributed` `# by ajit` |

## C#

`// C# program to find the` `// number of triangles in` `// a plane if no more then` `// two points are collinear.` `using` `System;` `class` `GFG` `{` ` ` `// Function to find number` ` ` `// of triangles in a plane.` ` ` `static` `int` `countNumberOfTriangles(` `int` `n)` ` ` `{` ` ` `// Formula to find number` ` ` `// of triangle` ` ` `// nC3 = n * (n - 1) *` ` ` `// (n - 2) / 6` ` ` `return` `n * (n - 1) *` ` ` `(n - 2) / 6;` ` ` `}` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `n = 4;` ` ` `Console.WriteLine(` ` ` `countNumberOfTriangles(n));` ` ` `}` `}` `// This code is contributed by anuj_67.` |

## PHP

`<?php` `// PHP program to find the` `// number of triangles in a` `// plane if no more then` `// two points are collinear.` `// Function to find number` `// of triangles in a plane.` `function` `countNumberOfTriangles(` `$n` `)` `{` ` ` `// Formula to find number` ` ` `// of triangles nC3 = n *` ` ` `// (n - 1) * (n - 2) / 6` ` ` `return` `$n` `* (` `$n` `- 1) *` ` ` `(` `$n` `- 2) / 6;` `}` `// Driver code` `$n` `= 4;` `echo` `countNumberOfTriangles(` `$n` `);` `// This code is contributed` `// by anuj_67.` `?>` |

## Javascript

`<script>` `// javascript program to find the number of` `// triangles in a plane if no more` `// then two points are collinear.` ` ` `// Function to find number of triangles` ` ` `// in a plane.` ` ` `function` `countNumberOfTriangles(n)` ` ` `{` ` ` `// Formula to find number of triangle` ` ` `// nC3 = n * (n - 1) * (n - 2) / 6` ` ` `return` `n * (n - 1) * (n - 2) / 6;` ` ` `}` ` ` `// Driver code` ` ` `var` `n = 4;` ` ` `document.write(countNumberOfTriangles(n));` `// This code is contributed by aashish1995` `</script>` |

**Output:**

4

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