using System;

public class Program

{

    static double intSurfCarre (double cote)

    {

        double surf = cote * cote;

        return surf ;

    }

    static void test ()

    {

        Console.WriteLine("Veuillez entrer la valeur d'un coté");

        double c = Convert.ToDouble(Console.ReadLine());

        double surface = intSurfCarre(c);

        Console.WriteLine( surface );

    }   

    public static void Main()

    {

        test();

    }

}

​