c#函数和练习

class Program
{
//访问修饰符 函数名（参数1，参数2）
//{
//函数体
//return 返回值
//}
/// <summary>
/// 无参数，无返回值
/// </summary>
public static void abc()
{
Console.WriteLine("无参数，无返回值");
}

/// <summary>
/// 无参数，有返回值
/// </summary>
/// <param name="args"></param>
public static int abc2()
{
return 1;
}

/// <summary>
/// 有参数，无返回值
/// </summary>
/// <param name="args"></param>
public static void abc3(int a, int b)
{
Console.WriteLine(a + b);
}
/// <summary>
/// 有参数，有返回值
/// </summary>
/// <param name="args"></param>
public static int abc4(int x, int y)
{
return x * y;
}
struct stu
{
public int id;
public string name;
public DateTime birthday;
public double mark;
public int age;
}

static void Main(string[] args)
{
abc();

Console.WriteLine(abc2());

abc3(1, 2);

Console.WriteLine(abc4(2, 3));

Console.WriteLine("请输入学生数");
int count = int.Parse(Console.ReadLine());
Console.WriteLine("请输入学生信息: ");

List<stu> st_list = new List<stu>();

for(int i = 1; i <= count; i++)
{
stu st;
 Console.WriteLine("请输入第"+ i +"个学生学号");
 st.id = int.Parse(Console.ReadLine());
 Console.WriteLine("请输入第" + i + "个学生姓名");
 st.name = Console.ReadLine();
 Console.WriteLine("请输入第" + i + "个学生生日");
 st.birthday = Convert.ToDateTime(Console.ReadLine());
 Console.WriteLine("请输入第" + i + "个学生分数");
 st.mark = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("请输入第" + i + "个学生年龄");
st.age = DateTime.Now.Year - st.birthday.Year;

 st_list.Add(st);
}

foreach(var x in st_list)
{
 Console.WriteLine(x.id+ " " + x.name + " " + x.birthday + " " + x.mark +" " + x.age + " ");
}

建立一个1-100的集合，让50-90最后出现：
ArrayList alt = new ArrayList();

for (int i = 1; i <= 100; i++)
{
alt.Add(i);
}

for (int i = 49, j = 90; i <= 58 && j <= 200; i++, j++)
{

alt.Insert(i, alt[j]);
j++;

}

foreach (int x in alt)
{
Console.WriteLine(x);
}

Console.ReadLine();
}
}