Question

用0-9这十个数字可以组成多少无重复的三位数?

显示无重复的三位数这部分我已经实现了，不过要求在另一个文本框中显示出总的个数，求教各位大虾，显示出总个数怎么实现？刚学这东西，头都搞晕了。
string s = "";
for (int a = 1; a <= 9; a++)
{
for (int b = 0; b <= 9; b++)
{
for (int c = 0; c <= 9; c++)
{
if (a != b && b != c && a != c)

s=s+(a * 100 + b * 10 + c).ToString()+" ";

tbx_Dispaly.Text = s;
}
}
}

Answer 1

string s = "";
int n = 0;
for (int a = 1; a <= 9; a++)
{
for (int b = 0; b <= 9; b++)
{
for (int c = 0; c <= 9; c++)
{
if (a != b && b != c && a != c)

s=s+(a * 100 + b * 10 + c).ToString()+" ";
n++;

//tbx_Dispaly.Text = s;
}
}
}
//这句话最好放循环体外面
tbx_Dispaly.Text = s;
txtCount.Text = n.ToString();

Answer 2

再定义一个变量``
初值为零``
你产生一个数就让它自加一次就行了``

不重复的三位数有一千个吧`

Answer 3

720

Answer 4

729