Method declaration and invocation

Topic description  

Method declaration and invocation. (console application)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace find factorial
{
    class Program
    {
        static void Factorial(int num)
        {
            int factorial = 1;
            for (int i = num; i > 0; i--)
                factorial *= i;
            Console.WriteLine("The factorial of {0} is: {1}",num,factorial);
        }
        static void Main(string[] args)
        {
            Factorial(8);
            Factorial(7);
            Factorial(6);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace summation
{
    class Program
    {
        static int Add(params int[] nums)//The number of params is not fixed
        {
            int sum = 0;
            foreach (int outnum in nums)
                sum += outnum;
            return sum;
        }

        static void Main(string[] args)
        {
            int[] myintArray={2,42,45,3,6,3,0};
            Console.WriteLine(Add(myintArray));
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace summation
{
    class Program
    {
        static void Square(int num)//value transfer
        {
            num *= num;
            Console.WriteLine("The square of num is: "+num);
        }
        static void Main(string[] args)
        {
            int num = 10;
            Console.WriteLine(num);
            Square(num);
            Console.WriteLine(num);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace summation
{
    class Program
    {
        static void Square(ref int num)//Pass by reference
        {
            num *= num;
            Console.WriteLine("The square of num is: "+num);
        }
        static void Main(string[] args)
        {
            int num = 10;
            Console.WriteLine(num);
            Square(ref num);
            Console.WriteLine(num);
        }
    }
}  

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace finds the maximum value and index of an array
{
    class Program
    {
        static int MaxNum(int[] nums,out int MaxNumIndex)
        {
            int maxNum = nums[0];
            MaxNumIndex = 0;
            for (int i = 0; i < nums.Length; i++)
            {
                if (maxNum < nums[i])
                {
                    maxNum = nums[i];
                    MaxNumIndex = i;
                }
            }
            return maxNum;
        }
        static void Main(string[] args)
        {
            int[] myintArray = { 1, 3, 5, 7, 8, 9 };
            int MaxNumIndex;
            Console.WriteLine("The maximum value of this array is {0}, and the index value of the maximum value is {1}",MaxNum(myintArray,out MaxNumIndex),MaxNumIndex);
        }
    }
}