C# Programming - Functions and Subroutines

namespace IndiabixConsoleApplication
{ 
    class SampleProgram
    {
        static void Main(string[] args)
        { 
            int num = 1;
            funcv(num); 
            Console.Write(num + ", "); 
            funcr(ref num); 
            Console.Write(num + ", ");
        }
        static void funcv(int num)
        { 
            num = num + 10; Console.Write(num + ", ");
        }
        static void funcr (ref int num)
        { 
            num = num + 10; Console.Write(num + ", ");
        } 
    } 
}

namespace IndiabixConsoleApplication
{ 
    class SampleProgram
    { 
        static void Main(string[] args)
        { 
            int[]arr = newint[]{ 1, 2, 3, 4, 5 }; 
            fun(ref arr);
        }
        static void fun(ref int[] a)
        { 
            for (int i = 0; i < a.Length; i++)
            { 
                a[i] = a[i] * 5; 
                Console.Write(a[ i ] + " "); 
            } 
        } 
    } 
}

1. An argument passed to a ref parameter need not be initialized first.
2. Variables passed as out arguments need to be initialized prior to being passed.
3. Argument that uses params keyword must be the last argument of variable argument list of a method.
4. Pass by reference eliminates the overhead of copying large data items.
5. To use a ref parameter only the calling method must explicitly use the ref keyword.

1. A function cannot be called from a subroutine.
2. The ref keyword causes arguments to be passed by reference.
3. While using ref keyword any changes made to the parameter in the method will be reflected in that variable when control passes back to the calling method.
4. A subroutine cannot be called from a function.
5. Functions and subroutines can be called recursively.