Sachin Kumar Sachin Kumar - 3 months ago 19
C# Question

Out parameter in c#

I am new to C#. I've tried this with out parameter in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class First
{
public void fun(out int m)
{
m *= 10;
Console.WriteLine("value of m = " + m);
}
}

class Program
{
static void Main(string[] args)
{
First f = new First();
int x = 30;
f.fun(out x);
}
}


but i get some errors like "Use of unassigned out parameter 'm'" and

The out parameter 'm' must be assigned to before control leaves the current method.

So what is the meaning of these errors and why it is compulsory to assign 'm' when i'm already assigned a value to x.

Answer

ref means that you are passing a reference to the variable that has been declared and initialized, before calling the method, and that the method can modify the value of that variable.

out means you are passing a reference to the variable that has been declared but not yet initialized, before calling the method, and that the method must initialize or set it's value before returning.