输出99乘法表
这个是倒着输出:
for (int i = 1; i < 10; i++)
{
for (int j = i; j < 10; j++)
{ Console.Write("{0}x{1}={2} ", i, j, i * j); }
Console.WriteLine();
}

=============================================================
这个是正着输出:
for (int i = 1; i < 10; i++)
{
for (int j = 1; j < i+1; j++)
{ Console.Write("{0}x{1}={2} ", i, j, i * j); }
Console.WriteLine();
}
