Description

Get the number of people in the room as input from the user. Then calculate the maximum number of handshakes possible among that people.

For e.g.

If there are N people in the room then the first person has to shake hand with N-1 people and second person has to shake hand with N-1-1 people i.e., N-2 handshakes are possible. Thus, it goes on.

So total hand shakes = N-1 + N-2 + N-3 +………+1 + 0

Input

10

Output

45

C Program

#include <stdio.h>

int main()

{

    int num;

    printf("Enter the number of people in the room: ");

    scanf("%d",&num);

    int total = num * (num-1) / 2;

    printf("Total handshakes = %d",total);

    return 0;

}

C++ Program

#include <iostream>

using namespace std;

int main()

{

    int num;

    cout<<"Enter the number of people in the room: ";

    cin>>num;

    int total = num * (num-1) / 2;

    cout<<"Total handshakes = "<<total;

    return 0;

}

Java

import java.util.Scanner;

public class Main

{

public static void main(String[] args) {

    Scanner sc=new Scanner(System.in);

System.out.print("Enter the number of people in the room: ");

int num = sc.nextInt();

int total = num * (num-1) / 2;

System.out.println("Total number of handshakes = "+total);

}

}

Python

num= int(input("Enter the number of people in the room: "))

total = int(num * ((num - 1) / 2))

print("Total number of handshakes = ",total)