程序以查找完整图中的边总数

给定一个图的N个顶点。任务是在N个顶点的完整图中找到可能的边总数。
完整图： “完整图”是其中每对顶点通过一条边连接的图。
例子：

Input : N = 3
Output : Edges = 3

Input : N = 5
Output : Edges = 10

在N个顶点的完整图中，可能的边总数为：

Total number of edges in a complete graph of N vertices = ( n * ( n – 1 ) ) / 2 
 

示例1：下面是一个完整的图形，其中N = 5个顶点。

上面完整图中的边总数= 10 =(5)*(5-1)/ 2。
下面是上述想法的实现：

C++

// C++ implementation to find the
// number of edges in a complete graph
 
#include 
using namespace std;
 
// Function to find the total number of
// edges in a complete graph with N vertices
int totEdge(int n)
{
    int result = 0;
 
    result = (n * (n - 1)) / 2;
 
    return result;
}
 
// Driver Code
int main()
{
    int n = 6;
 
    cout << totEdge(n);
 
    return 0;
}

Java

// Java implementation to find the
// number of edges in a complete graph
 
class GFG {
     
// Function to find the total number of
// edges in a complete graph with N vertices
static int totEdge(int n)
{
    int result = 0;
 
    result = (n * (n - 1)) / 2;
 
    return result;
}
 
    // Driver Code
    public static void main(String []args)
    {
        int n = 6;
        System.out.println(totEdge(n));
    }
 
}

Python 3

# Python 3 implementation to 
# find the number of edges
# in a complete graph
 
# Function to find the total
# number of edges in a complete
# graph with N vertices
def totEdge(n) :
 
    result = (n * (n - 1)) // 2
 
    return result
             
# Driver Code
if __name__ == "__main__" :
 
    n = 6
 
    print(totEdge(n))
 
# This code is contributed
# by ANKITRAI1

C#

// C# implementation to find
// the number of edges in a
// complete graph
using System;
 
class GFG
{
     
// Function to find the total
// number of edges in a complete
// graph with N vertices
static int totEdge(int n)
{
    int result = 0;
 
    result = (n * (n - 1)) / 2;
 
    return result;
}
 
// Driver Code
public static void Main()
{
    int n = 6;
    Console.Write(totEdge(n));
}
}
 
// This code is contributed
// by ChitraNayal

Javascript

 
// Javascript implementation to find the
// number of edges in a complete graph
 
// Function to find the total number of
// edges in a complete graph with N vertices
function totEdge(n)
{
    var result = 0;
 
    result = (n * (n - 1)) / 2;
 
    return result;
}
 
// Driver Code
var n = 6;
document.write( totEdge(n));
 

输出：

15