C# Language Value type vs Reference type ref vs out parameters
Example
Code
class Program
{
static void Main(string[] args)
{
int a = 20;
Console.WriteLine("Inside Main - Before Callee: a = {0}", a);
Callee(a);
Console.WriteLine("Inside Main - After Callee: a = {0}", a);
Console.WriteLine();
Console.WriteLine("Inside Main - Before CalleeRef: a = {0}", a);
CalleeRef(ref a);
Console.WriteLine("Inside Main - After CalleeRef: a = {0}", a);
Console.WriteLine();
Console.WriteLine("Inside Main - Before CalleeOut: a = {0}", a);
CalleeOut(out a);
Console.WriteLine("Inside Main - After CalleeOut: a = {0}", a);
Console.ReadLine();
}
static void Callee(int a)
{
a += 5;
Console.WriteLine("Inside Callee a : {0}", a);
}
static void CalleeRef(ref int a)
{
a += 10;
Console.WriteLine("Inside CalleeRef a : {0}", a);
}
static void CalleeOut(out int a)
{
// can't use a+=15 since for this method 'a' is not intialized only declared in the method declaration
a = 25; //has to be initialized
Console.WriteLine("Inside CalleeOut a : {0}", a);
}
}
Output
Inside Main - Before Callee: a = 20
Inside Callee a : 25
Inside Main - After Callee: a = 20
Inside Main - Before CalleeRef: a = 20
Inside CalleeRef a : 30
Inside Main - After CalleeRef: a = 30
Inside Main - Before CalleeOut: a = 30
Inside CalleeOut a : 25
Inside Main - After CalleeOut: a = 25
