摘要：分析：n的位数等于(int)log10(n) +1 例如3的位数是(int)log10(3)+1 = 1 ，52的位数是(int)log10(52)+1 = 2 所以一个数n的阶乘的位数是: (int)log10(n!)+1 = (int)log10(n*(n-1)*(n-2)*...*2*1)+1 = (int)(log10(n)+log10(n-1)+log10(n-2)+...+log10(2)+log10(1))+1 用C++实现的话，就是(int)(log(n)+log(n-1)+log(n-2)+...+log(2)+log(... 阅读全文