for(【初始化表達式】;【條件表達式】;【迭代表達式 】)
{
          //語句塊
}

for (int num = 1; num < 0; num++)
{
    Response.Write(num);
}

Response.Write("結果：<br />" );
for (int num = 1; num < 5; ++num)
{
    Response.Write(num + "<br />");
}

int tmp = 0;
i = 1;
i = tmp; 

for (int i = 9; i-- > 0; )
{
    Response.Write(i);
}

for (int i = 10; i-- > 0; )
{
    Response.Write(i);
}

for (int i = 9,j = 1; i > 0&&j < 5; i--,j++)
{
    Response.Write(i + "*" + j + "=" +  i*j + "<br />");
}

for循環支持多表達式，上面的執行結果是：


例子五：

for(;;)
{
}