实现n！+（n-1)!+...+1!

int jc(int p, int i)

{

for (; i != 1; i -= 1)

p *= i;

return p;

};

int p = 1;

int i = 0;

int sum = 0;

int x = 0;

int main()

{

/*printf（"n");*/

printf("请输入n");

scanf_s("%d", &i);

for (; i!= 0; i--)

{

x = jc(p, i);

sum += x;

}

printf("%d", sum);

}