C :

#include<stdio.h>
int main()
{
	float a,b,c,s=0;
	int n,i;
	scanf("%d",&n);
	a=1;
	b=2;
	for(i=0;i<n;i++)
	{
		s=s+b/a;
		c=a+b;
		a=b;
		b=c;
	}
	printf("s=%.2f\n",s);
}

C++ :

#include<stdio.h>
#include<math.h>
int main()
{
	float a,b,c,s=0;
    int i,n;
    scanf("%d",&n);
    a=1;
    b=2;
    for(i=1;i<=n;i++)
   {
  	s=s+1.0*b/a;
  	c=a+b;
  	a=b;
  	b=c;
   }
   printf("s=%.2f\n",s);
}

Java :

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[][] a = new int[n][n];
        a[0][0] = 1;
        a[0][1] = 2;
        for (int i = 1 ; i<n;i++){
            a[i][0] =a[i-1][1];
            a[i][1]=a[i-1][0]+a[i-1][1];
        }
        float sum = 0;
        for (int i = 0 ; i < n ; i++){
            sum += chu(a[i][0],a[i][1]);
        }
        System.out.printf("s=%.2f",sum);
    }
    public static float chu(int a,int b){
        return (float)b/a;
    }
}

Python :

# coding=utf-8
#python2
n = int(input())
s = 0
a = 2
b = 1
for i in range(1,n+1):
    s += float(a) / b
    t = b
    b = a
    a = t + b
print('s=%.2f'%s)

C# :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    internal class Program
    {
        static void Main()
        {

            int n = Convert.ToInt32(Console.ReadLine());
        
            double s =0;
            double a = 1;
            double b = 2;
            double c = a;
            double x = 0;
            for (int i = 1; i <= n; i++)
            {
                x =b / a;
                s = s + x;
                c = a;
                a = b;
                b = c+b;
                
            }
            Console.WriteLine("s="+Math.Round(s, 2).ToString("0.00"));
            Console.ReadKey();

        }
    }
}