C++ program to find out the nth terms of its factorial

#include<iostream>
#include<conio.h>

int main()
{
    int i,n;
    float res,j,k;
system("cls");

    std::cout<<"Enter any number you want to series = ";
    std::cin>>n;

    res = 1;
    k = 0;

    for(i=1;i<=n;i++)
    {
        res = res*i;
        j = i/res;
        k = k+j;
    }

    std::cout<<"1/1! + 2/2! + 3/3! + 4/4! + ... + n/n! = "<<k;

    getch();
    return 0;
}

Enter any number you want to series = 5
1/1! + 2/2! + 3/3! + 4/4! + .... + n/n! = 2.708333