「基础」C#中的循环

public partial class Cyc : System.Web.UI.Page
...{
    protected void Page_Load(object sender, EventArgs e)
    ...{
        string str = "123456789";
        for (int i = 0; i < str.Length; i++ )
        ...{
            Response.Write(str[i].ToString()+"<br/>");
        }
        Response.Write("<hr/>");
        int j = 0;
        do
        ...{
            Response.Write(j+"<br/>");
            j++;
        }
        while(j < 3);
        Response.Write("<hr/>");
        int k = 0;
        while(k < 3)
        ...{
            Response.Write(k+"<br/>");
            k++;
        }
        Response.Write("<hr/>");
        string[] strArr = new string[] ...{"1wantianwen","2lishanshan","3chaoren","4suochao","5xiecheng"};
        foreach(string tempArr in strArr)
        ...{
            if (tempArr.Contains("a"))
            ...{
                Response.Write("<font color=red>" + tempArr.ToString() + "</font><br/>");
            }
            else
            ...{ 
                Response.Write(tempArr+"<br/>");
            }
        }
    }
}