C :

#include<stdio.h>
int main()
{
	int a,i;
	double t,q,s;
	i=1;
	q=1;
	s=1;
	scanf("%d",&a);
	while(i<=a)
	{
		s=s*i;
		t=1/s;
		q=q+t;
		i++;
	}
	printf("%.5lf",q);
	return 0;
}

C++ :

#include<stdio.h>
int main ()
{
	int n,i,jc = 1;
	double e = 1;
	scanf("%d",&n);
	for (i = 1; i <= n; i ++)
	{
		jc = jc * i;
		e = e + 1.0 / (double)jc;
	
	}
		printf("%.5lf\n",e);
	return 0 ;
}

Pascal :

program xzy2;
  var
    e:real;
    n,i,j,x:int64;
  begin
    readln(n);
    e:=1;
    x:=1;
    for i:=1 to n do
      begin
      for j:=1 to i do
        x:=x*j;
      e:=e+1/x;
      x:=1;
      end;
    write(e:0:5);
  end.