optional parameter write methods

Question

Hi all i am a absolute beginner of c#5.0 and i want to understand how the Console.Writeline is different for optional parameters e.g

class test
{
static void Prg(int a=0,int b=0,int c=0,int d=0)
{Console.Writeline(a,b,c,d);}
static void Main()
{
Prg();
}

i want to print values for a,b,c,d as 0 0 0 0 in o/p

but iit shows error as 'overload method has some invalid arguments.

tell me methods for Console.Write() for this code,thanks in advance.

Khan Abrar Ahmed · Answer

Hi you can use this for optional parameter Console.WriteLine ({0} {1} {2}{3}abcd);

Vulpes · Answer

The Console.WriteLine() method has 19 overloads but only one of them can deal with an arbirary number of parameters namely: WriteLine(string format params Object[] arg) Basically the C# compiler first tries to fit one of the overloads which take a fixed number of parameters depending on their type and number to what you have written in your source code. If it can't find a match it then tries the above overload and if that doesn't match either it issues an error. So whilst this didn't match any overload: Console.Writeline(a b c d); this one matched the overload which takes an arbitrary number of parameters: Console.WriteLine({0} {1} {2} {3} a b c d); because of course an object array can hold values of any type including int. The first parameter formats the parameters by separating them with a space and a comma. {0} {1} {2} etc. are what's called 'placeholders' for the subsequent parameters.

Hemant Sharma · Answer

I wants a single instruction in Prg method to print all optional parameter's values.

Khan Abrar Ahmed · Answer

HI can you please let us know what output you want like 0000 or 0 0 0 0

Hemant Sharma · Answer

But i found Console.Writeline(a++b); if there are only two optional parameters ab and it works but for all abcd i don't knowi saw that e.g in optional parameters.

Khan Abrar Ahmed · Answer

hi you can use two thing. class test { static void Prg(int a=0int b=0int c=0int d=0) { Console.Writeline(a.tostring()); Console.Writeline(b.tostring()); Console.Writeline(c.tostring()); Console.Writeline(d.tostring()); } static void Main() { Prg(); } or Console.WriteLine ({0} {1} {2}{3} // a // b cd);