Error "The name 'xxx' does not exist in the current context"

[eschwartz]

Within a switch function in a method, I get an error "The name 'Radius' does not exist in the current context." The varible is assigned elsewhere in the code. I don't get the error for the other variables.

public static double MenuItem(int amount)  // method based on menu selection
        {
            double Volume;
            // double Radius;
            double Number = Radius;
 
           // if (amount < 1 || amount > 3)
             //   amount = 4;
 
            switch (amount)
            {
                case 1:
                    Volume = 4 / 3 * Math.PI * Math.Pow (Radius, 3);
                    break;
                case 2:
                    double Length, Width, Height;
                    Volume = Length * Width * Height;
                    break;
                case 3:
                    Volume = Math.PI * Math.Pow (Radius, 2) * Height;
                    break;
                default:
                    Console.WriteLine("Your response was out of the expected range");
                    Volume = 0;
                    //Radius = 1;
                    //Length = 1;
                    //Width = 1;
                    //Height = 1;
                    break;
            }
            Console.WriteLine("");
            return Volume;
            }

[Rabbit]

We need to see how and where it is declared and populated.

[eschwartz67]

Here is the code after I have made some changes. Now the error I am getting is "Use of unassigned local variable 'Volume.'

  Console.WriteLine("This program will compute the volume of a 3-D shape.");
 
            double Volume;
 
            SkipLine();
 
            Console.WriteLine("Computation Menu");
            SkipLine();
            Console.WriteLine("1  Volume of a Sphere");
            Console.WriteLine("2  Volume of a Rectangular Prism");
            Console.WriteLine("3  Volume of a Cylinder");
            SkipLine();
 
            int Response = AskUserForNumber("the number corresponding to the 3-D shape volume you want to       compute:");
 
            do
            {
 
            if (Response < 1 || Response > 3)   // is the entry between 1 and 3?
            {
                SkipLine();
                Console.WriteLine("The number you entered is out of the expected range");
                SkipLine();
                Response = AskUserForNumber("the number corresponding to the 3-D shape volume you want to compute:");
                SkipLine();
            }
            } while (Response < 1 || Response > 3); // Keep going until Response is between 1 and 3
 
 
           // if (Response == 1)
            //{
            //    double SphereRadius = AskUserForNumber("the radius of the Sphere:");
            //}
 
            //if (Response == 2)
            //{
             //   double PrismLength = AskUserForNumber("the length of the Rectangular Prism:");
            //}
            //if (Response == 2)
            //{
             //   double PrismWidth = AskUserForNumber("the width of the Rectangular Prism:");
            //}
            //if (Response == 2)
            //{
             //   double PrismHeight = AskUserForNumber("the height of the Rectangular Prism:");
            //}
           // if (Response == 3)
            //{
             //   double CylinderRadius = AskUserForNumber("the radius of the Cylinder:");
            //}
            //if (Response == 3)
            //{
            //    double CylinderHeight = AskUserForNumber("the height of the Cylinder:");
            //}
 
            SkipLine();
 
            MenuItem(Response);
 
            SkipLine();
            SkipLine();
 
           // Console.WriteLine(Length + " " + Width + " " + Height + " " + Radius);
 
            //double Answer = Math.Pow (Length, 3);
            //double Answer = Length * Length * Length;
 
            //Console.WriteLine("Answer is " + Answer);
 
            Console.WriteLine("The volume of the 3-D shape you selected is " + Volume);
 
            SkipLine();
 
            EndProgram();
        }
 
        public static int AskUserForNumber(string specificQuestion)
        {
            Console.WriteLine("Please enter {0}", specificQuestion);
            string theirInput = Console.ReadLine();
            int aIntValue = Convert.ToInt32(theirInput);
            return aIntValue;
        }
 
 
        public static double MenuItem(int amount)  // method based on menu selection
        {
            double Volume = 1;
            switch (amount)
            {
                case 1:
                    double SphereRadius = AskUserForNumber("the radius of the Sphere:");
                    Volume = 4 / 3 * Math.PI * Math.Pow(SphereRadius, 3);
                    break;
                case 2:
                    double PrismLength = AskUserForNumber("the length of the Rectangular Prism:");
                    SkipLine();
                    double PrismWidth = AskUserForNumber("the width of the Rectangular Prism:");
                    SkipLine();
                    double PrismHeight = AskUserForNumber("the height of the Rectangular Prism:");
                    SkipLine();
                    Volume = PrismLength * PrismWidth * PrismHeight;
                    break;
                case 3:
                    double CylinderRadius = AskUserForNumber("the radius of the Cylinder:");
                    SkipLine();
                    double CylinderHeight = AskUserForNumber("the height of the Cylinder:");
                    SkipLine();
                    Volume = Math.PI * Math.Pow(CylinderRadius, 2) * CylinderHeight;
                    break;
                default:
                    Console.WriteLine("Your response was out of the expected range");
                    Volume = 0;
                    //Radius = 1;
                    //Length = 1;
                    //Width = 1;
                    //Height = 1;
                    break;
            }
            Console.WriteLine("");
            return Volume;
            }
 
        public static void HitAnyKeyToContinue()
        {
            Console.WriteLine("Hit any key to continue. . .");
            Console.ReadKey();
            Console.WriteLine("");
        }
 
        public static void EndProgram()
        {
            Console.WriteLine("Press any key to end program...");
            Console.ReadKey();
        }
 
        public static void SkipLine()
        {
            Console.WriteLine("");
        }
    }

The erro is in this line:

Console.WriteLine("The volume of the 3-D shape you selected is " + Volume);

[Rabbit]

Please use code tags when posting code.

The problem is that you never assign a value to your volume variable on line 3 in whatever that function is.

[M1kkelZU]

So basically you would need to assign a base value, am I right Rabbit?
so something like

double Example = 0;

[Rabbit]

Yes. That is the crux of the problem. But after you fix that problem, you will notice a new one. That volume isn't getting set when you call your MenuItem function. And that's because you're not assigning the return value to the varible on line 58.