Question

C语言：编写程序求sum=1/1!+1/2!+1/3!+ …1/n!,n为输入且20≥n≥3.

Answer 1

main()
{
int i,j,k;
float sum=0;
clrscr();
scanf("%d",&n);
if(n>=3&&n<=20)
{
for(i=1;i<=n;i++)
{k=1;
for(j=1;j<=i;j++)
k=k*j;
sum=sum+1.0/k;
}
printf("%d",sum);
}
else
printf("wrong");
}

Answer 2

#include <stdio.h>
void main()
{
int i,n;
double sum=0,p=1;
printf("Please Input n:");
scanf("%d",&n);
if(n>=3&&n<=20)
{
for(i=1;i<=n;i++)
{
p=p*i;
sum=1/p+sum;
}

printf("sum=%f\n",sum);
}
else
printf("20≥n≥3 needed\n");
}