c语言求阶乘n!的第m位数码,怎么求?

c语言求阶乘n!的第m位数码,怎么求?

int jiecheng(int n)

{
if (0 >= n)

return 1;

return n * (n - 1);

}

int shuma(int m, int jiecheng)
{
int i = 0, tmp = 0;
tmp = jiecheng;

if (0 >= m)

return -1;

if (m * 10 > tmp)

return 0;

for (i = 0;i < m - 1;i++)

tmp /= 10;
tmp %= 10;

return tmp;

}