C :

#include <stdio.h>
int total(int n);

int main(int argc, char const *argv[])
{
	int n;
	scanf("%d",&n);
	double sum = 0;
	for (int i = 1; i <= n; ++i)
	{
		sum += 1.0/total(i);
	}
	printf("s=%lf\n",sum);
}

int total(int n)
{
	int sum = 0;
	for (int i = 1; i <= n; ++i)
	{
		sum += i;
	}
	return sum;
}

C++ :

#include<iostream>
using namespace std;

int total(int);
int main() {
	double s = 0.0;
	int n;
	cin >> n;
	for(int i=1; i<=n; ++i){
		s += (1.0 / total(i));                //一定是total(i),不是total(n)
	}
	printf("s=%.6f\n", s);
	return 0;
}

int total(int x) {
	int sum = 0;
	for(int i=1; i<=x; ++i){
		sum += i;
	}
	return sum;
}

C# :

using System;

namespace ACMclubzjicm
{
    class Test_1341
    {
        static void Main()
        {
            int numIn = GetNum();
            double s = 0;
            for (int i = 1; i <= numIn; i++)
            {
                s += 1 / (double)total(i);
            }
            Console.Write("s={0:F6}", s);
            return;
        }

        private static int GetNum()
        {
            string stIn = Console.ReadLine().Trim();
            int numIn = int.Parse(stIn);
            return numIn;
        }

        private static int total(int num)
        {
            int sum = 0;
            for (int i = 1; i <= num; i++)
            {
                sum += i;
            }
            return sum;
        }
    }
}