A detailed example of the c language factorial summation problem

Topic describes

S=1! + 2! + 3! +... + n! (n 50 or less)

Among them "! Represents the factorial, for example: 5! = 5 * 4 * 3 * 2 * 1.

Inputoutput format

Input format:

1 positive integer N.

Output format:

1 positive integer, S, represents the calculation result.

I/O sample

Enter the sample

3

The output sample

9

#include<stdio.h>
int fun(int n)
{
 if(n==1||n==0)
 {
 return 1;
 }
 if(n>1)
 {
 return fun(n-1)*n;
 }
}
int main()
{
 int N,i,sum=0;
 scanf("%d",&N);
 for(i=1;i<=N;i++)
 {
 sum=sum+fun(i);
 }
 printf("%d\n",sum);
 return 0;
}

or

#include<stdio.h>
int main()
{
 int N,i,sum=0,t,h;
 scanf("%d",&N);
 for(i=1;i<=N;i++)
 {
 t=1;
    h=i;
 while(h)
 {
  t=t*h;
  h--;
 }
 sum=sum+t;
 }
 printf("%d\n",sum);
 return 0;
}

or

#include<stdio.h>
#include<String.h>
int main()
{
 int N,i,sum=0,t=1;
 int f,p=0; 
 scanf("%d",&N);
 for(i=1;i<=N;i++)
 {
 t=i*t; 
 f=p+t;
 p=f;
 
 }
 printf("%d\n",f);
 return 0;
}

conclusion