Calling a method within the same class

Tim D Published at Dev

Tim D

I am working on a simple program to generate an array of values and perform some basic computations on them. I am having problems calling my "Mean" and "Median" methods from the Main method. I've attached the compiler error below. Thank you.

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

namespace ConsoleApplication4
{
    class arraymod
    {
        static void Main(string[] args)
        {
            int[] values;
            values = new int[10];
            Random rand = new Random();
            for (int i = 0; i < 10; i++)
            {
                values[i] = rand.Next(1,20);
            }

            Array.Sort(values);
            for (int i = 0; i < 10; i++)
            {
                Console.WriteLine(values[i]);
            }
            Console.WriteLine("Min: {0}", values.Min());
            Console.WriteLine("Max: {0}", values.Max());
            Console.WriteLine("Sum: {0}", values.Sum());
            Console.WriteLine("Mean: {0}", values.Mean()); //program fails here
            Console.WriteLine("Median: {0}", values.Median());
        }
        public int Mean(int[] arr)
        {
            int valuesMean = arr.Sum()/arr.Count();
            return valuesMean;
        }
        public int Median(int[] arr)
        {
            int valuesMedian = (arr.Max()+ arr.Min())/2;
            return valuesMedian;
        }
    }
}

arraymod.cs(29,42):

error CS1061: 'System.Array' does not contain a definition for 'Mean' and no extension method 'Mean' accepting a first argument of
type 'System.Array' could be found (are you missing a using directive or an assembly reference?)

Shoring

It's not a extension method. You need to make methods static and call them:

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

namespace ConsoleApplication4
{
class arraymod
{
    static void Main( string[] args )
    {
        int[] values;
        values = new int[ 10 ];
        Random rand = new Random();
        for( int i = 0 ; i < 10 ; i++ )
        {
            values[ i ] = rand.Next( 1 , 20 );
        }

        Array.Sort( values );
        for( int i = 0 ; i < 10 ; i++ )
        {
            Console.WriteLine( values[ i ] );
        }
        Console.WriteLine( "Min: {0}" , values.Min() );
        Console.WriteLine( "Max: {0}" , values.Max() );
        Console.WriteLine( "Sum: {0}" , values.Sum() );
        Console.WriteLine( "Mean: {0}" , Mean( values ) ); //call
        Console.WriteLine( "Median: {0}" , Median( values ) );//call
    }
    //make method "Mean" static
    public static int Mean( int[] arr )
    {
        int valuesMean = arr.Sum() / arr.Count();
        return valuesMean;
    }
    //make method "Median" static
    public static int Median( int[] arr )
    {
        int valuesMedian = ( arr.Max() + arr.Min() ) / 2;
        return valuesMedian;
    }
}
}

Or use extension method:

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

namespace ConsoleApplication4
{
static class arraymod
{
    static void Main( string[] args )
    {
        int[] values;
        values = new int[ 10 ];
        Random rand = new Random();
        for( int i = 0 ; i < 10 ; i++ )
        {
            values[ i ] = rand.Next( 1 , 20 );
        }

        Array.Sort( values );
        for( int i = 0 ; i < 10 ; i++ )
        {
            Console.WriteLine( values[ i ] );
        }
        Console.WriteLine( "Min: {0}" , values.Min() );
        Console.WriteLine( "Max: {0}" , values.Max() );
        Console.WriteLine( "Sum: {0}" , values.Sum() );
        Console.WriteLine( "Mean: {0}" , values.Mean() ); //call
        Console.WriteLine( "Median: {0}" , values.Median() );//call
    }
    //use extension method
    public static int Mean( this int[] arr )
    {
        int valuesMean = arr.Sum() / arr.Count();
        return valuesMean;
    }
    //use extension method
    public static int Median( this int[] arr )
    {
        int valuesMedian = ( arr.Max() + arr.Min() ) / 2;
        return valuesMedian;
    }
}
}

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