#include <stdio.h> int main () { int n; int m=1; double x=0.0; scanf("%d",&n); for (int i=1;i<=n;i++) { m*=i; x+=1.0/m; } printf("%.2f",x); return 0; }

#include<stdio.h>
int main(){
	
	float i,term=0,sum=1;
	int n;
	scanf("%d",&n);
	for(i=1;i<=n;i++){
		sum*=i;
	
	term+=1/sum;
}
	printf("%.2f",term);
	
	
	return 0;
}

#include<stdio.h> //计算阶乘的函数factorial int factorial(int num) { int i ,a = 1; for(i = 1;i<=num;i++) { a*=i; } return a; } int main() { int n; //定义变量n double sum = 0.0; scanf("%d",&n); for(int i = 1;i<=n;i++) { sum +=(1.0/factorial(i)); } printf("%.2lf",sum); return 0; }

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

#include <stdio.h> int main() { int n; double num=0; scanf("%d",&n);

for(int i=1;i<=n;i++){ double x=1.0; for(int j=1;j<=i;j++){ x*=j; } num+=1/x; } printf("%.2f",num); return 0;

}

#include <stdio.h>
int main()
{
    int sp(int a);
    int a,b;
    scanf("%d",&a);
    double s=0.0;
    b=1;
    while(b<=a)
    {
        s=s+1.0/sp(b);
        b++;
    }
    printf("%.2lf",s);
    return 0;
}
int sp(int a)
{
    int i=1,c=1;
    while(i<=a){c=c*i;i++;}
    return c;
}//

#include<stdio.h> int main() { int n; double sum=0.00,s=1; scanf("%d",&n); for(int i=1;i<=n;i++){ s*=i; sum+=1/s; } printf("%.2lf",sum); return 0; }

#include<iostream> #include<iomanip> using namespace std;

int main() { int n; cin>>n; int i=1; float b=1.00,sum=0.00; while(i<=n) { b=b*i; sum+=1/b; i++; } cout<<fixed<<setprecision(2)<<sum<<endl;

return 0; }

#include<stdio.h> int main(){ int n; double a=1.0,b=0.0; scanf("%d",&n); for(int i=1.0;i<=n;i++){ a=a*i ,b=b+1/a; } printf("%.2lf",b); return 0; }

#include <stdio.h>
int jiecheng(int k)
{
	if(k==1) return 1;
	else return jiecheng(k-1)*k;
}
int main()
{
	int n; 
	double sum=0;
	scanf("%d",&n);
	for(int k=1;k<=n;k++)
		{
		sum+= 1.0/jiecheng(k);
		}
	printf("%.2f",sum);	
	return 0;
}
相比只加了一个阶乘（业余玩家写写玩）