when we write the following code. Output comes 3 why not 9

Question

when we write the following code. Output comes 3 why not 9
{
class Program
{
static void Sqr(int x)
{
x = x * x;
}
static void Main(string[] args)
{
int a = 3;
Sqr(a);

Console.WriteLine(a);
}
}
}

Answer 1

the output is 3 because x is only changed within the function. if you wish for it to be changed outside it do:

static void Sqr(ref int x)
and
Sqr(ref a)

then you'll see the output being 9

Answer 2

kp kalia do like this to get answer as 9:

a = Sqr(a);
and in method , do return x changing function return type as int from void..