值参数
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Test
{
class Program
{
public void testA(int x)
{
x = x + 10;
Console.WriteLine(x);
}
static void Main(string[] args)
{
int a = 100;
Program t = new Program();
t.testA(a);
Console.WriteLine(a);
}
}
}
结果:
引用参数
关键字:ref(函数中及调用时都要加ref);
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Test
{
class Program
{
public void testA(ref int x)
{
x = x + 10;
Console.WriteLine(x);
}
static void Main(string[] args)
{
int a = 100;
Program t = new Program();
t.testA(ref a);
Console.WriteLine(a);
}
}
}
结果:
输出参数
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Test
{
class Program
{
public void testA(out int x)
{
x = 1;
x = x + 10;
Console.WriteLine(x);
}
static void Main(string[] args)
{
int a = 100;
Program t = new Program();
t.testA(out a);
Console.WriteLine(a);
}
}
}
运行结果:
out类型的参数与ref类型的参数非常相似,它们传递的都是参数的引用,但是有几点关键区别:
- 未赋值的变量不可用于ref参数,但可用于out参数;
- 方法内给out参数赋值之前不能使用此参数;
- 方法内必须给out参数赋值。