4-7

#include<stdio.h>
int main(void)
{
    int i,j;
    double item,sum;

    sum=0;
        for(i=1;i<=100;i++){
            item=1;
            for(j=1;j<=i;j++)
                item=item*j;
            sum=sum+item;
        }
        printf("1!+2!+...+100!=%e\n",sum);
        
        return 0;
}