【c#语法】占位符， out, ref

占位符

//使用占位符，显示顺序是按照占位符
Console.WriteLine("The first is {0}, second is {1}, third is {2}", a, b, c);
//不使用占位符显示
Console.WriteLine("The first is " + a + " second is " + b + " third is " + c);
Console.ReadKey();

out

public static void change(out int a, out int b, out int c) {
a=10;
b=20;
c=30;
}

int a ;
int b ;
int c ;
change(out a, out b, out c);//a=10, b=20,c=30

ref

//交换函数
public static void swap(ref int a, ref int b) {
int temp = a;
a= b;
b=temp;
}

int a=1;
int b =2;
swap(ref a, ref b);