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;
}