C :

#include<stdio.h>
int main()
{
	float a,b,c;
	scanf("%f,%f,%f",&a,&b,&c);
	printf("%.2f",(a+b)*c/2);
	
}

C++ :

#include<stdio.h>
#include<math.h>
int main()
{
    double a,b,c,s;
    //freopen("1021A2.in","r",stdin);
    //freopen("1021A2.out","w",stdout);
    scanf("%lf,%lf,%lf",&a,&b,&c);
    s=(a+b)*c/2.0;
    printf("%.2lf\n",s);
    return 0;
}

Java :

import java.util.Scanner;
public class Main {
    public static void main(String[] agrs){
        Scanner input=new Scanner(System.in);
        String s1=input.nextLine();
        String[] x=s1.split(",");
        double sd=Double.parseDouble(x[0]);
        double xd=Double.parseDouble(x[1]);
        double h=Double.parseDouble(x[2]);
        double s=(sd+xd)*h/2;
        System.out.println(String.format("%.2f",s));
    }
}

Python :

# coding=utf-8
#python2
u,d,h=map(float,raw_input().split(','))
s=float((u+d)*h/2)
print("%.2f"%s)

C# :

using System;
using System.Collections.Generic;
using System.Diagnostics.SymbolStore;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    internal class Program
    {
        static void Main()
        {
            //int[] days = { 31,28,31,30,31,30,31,31,30,31,30,31};
            string[] a1 = Console.ReadLine().Split(',');
            double r = Convert.ToDouble(a1[0]);
            double b = Convert.ToDouble(a1[1]);
            double h = Convert.ToDouble(a1[2]);
            float pi = 3.1415926f;
            string S = ((r + b) * h / 2).ToString("0.00");

            Console.WriteLine(S);

            Console.ReadKey();

        }
    }
}