C :

#include<stdio.h>
int main()
{
	int a,b,c;
	float average;
	scanf("%d%d%d",&a,&b,&c);
	average=(a+b+c)/3.0;
	printf("%.3f\n",average);
	return 0;
}

C++ :

#include<stdio.h>
int main()
{
	int a,b,c;
	float s;
	//freopen("1012A5.in","r",stdin);
	//freopen("1012A5.out","w",stdout);
	scanf("%d%d%d",&a,&b,&c);
	s=(a+b+c)/3.0;
	printf("%.3f",s);
	return 0;
}

Java :

import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a,b,c;
		a = scan.nextInt();
		b = scan.nextInt();
		c = scan.nextInt();
		System.out.println(String.format("%.3f",(a+b+c)/3.0));
	}
}

Python :

# coding=utf-8
#python2
a,b,c=map(int,raw_input().split())
s=(a+b+c)/3.0
print("%.3f"%s)

C# :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    internal class Program
    {
        static void Main()
        {
            string[] m= Console.ReadLine().Split(' ');
            double a = Convert.ToDouble(m[0]);
            double b = Convert.ToDouble(m[1]);
            double c = Convert.ToDouble(m[2]);







            string z = ((a + b + c) / 3).ToString("0.000");

            float v = 1.9f;

            Console.WriteLine(z);
            Console.ReadKey();

        }

    }
}