4-6

#include<stdio.h>

double fact (int n);

int main(void)

{

         int i;

         double sum;

         sum=0;

         for(i=1;i<=100;i++)

                   sum=sum+fact(i);

         printf("1!+2!+...+100!=%e\n",sum);

 

         return 0;

}

double fact(int n)

{

         int i;

         double result;

 

         result=1;

         for(i=1;i<=n;i++)

                   result=result*i;

 

         return result;

 

}