Can't use a variable in another method in XNA - for-loop

Question

I will explain in depth after. So here is my code, we have an Elevation[] variable and each Elevation gets a random number:
public void elevation()
{
for (x = (int)Width - 1; x >= 0; x--)
{
for (y = (int)Width - 1; y >= 0; y--)
{
y = rand.Next((int)MaxElevation); //random number for each y.
Elevation[x] = y; //each Elevation gets a random number.
}
}
}
After this I try to use this random number in the draw method like this:
public void Draw(SpriteBatch spriteBatch)
{
for (x = (int)Width - 1; x >= 0; x--)
{
spriteBatch.Draw(Pixel, new Rectangle((int)Position.X + x, (int)Position.Y - Elevation[x], 1, (int)Height), Color.White);
//HERE, I try to acces the random number for each Elevation (y value). But I get 0 everywhere.
}
}
How can I acces this random number?
If I do that:
public void Draw(SpriteBatch spriteBatch)
{
for (x = (int)Width - 1; x >= 0; x--)
{
for (y = (int)Width - 1; y >= 0; y--)
{
y = rand.Next((int)MaxElevation);
spriteBatch.Draw(Pixel, new Rectangle((int)Position.X + x, (int)Position.Y - Elevation[y], 1, (int)Height), Color.White);
}
}
}
I will be able to acces the random numbers, but it will update every frame and the random numbers will change. So I need to calculate them once and then use them.
Here is all the code:
namespace procedural_2dterrain
{
class Terrain
{
Texture2D Pixel;
Vector2 Position;
Random rand;
int[] Elevation;
float MaxElevation;
float MinElevation;
float Width;
float Height;
int x;
int y;
public void Initialize( ContentManager Content, float maxElevation, float minElevation, float width, float height, Vector2 position)
{
Pixel = Content.Load<Texture2D>("pixel");
rand = new Random();
Elevation = new int[(int)width];
MaxElevation = maxElevation;
MinElevation = minElevation;
Width = width;
Height = height;
Position = position;
elevation();
}
public void Update()
{
}
public void elevation()
{
for (x = (int)Width - 1; x >= 0; x--)
{
for (y = (int)Width - 1; y >= 0; y--)
{
y = rand.Next((int)MaxElevation);
Elevation[x] = y;
}
}
}
public void Draw(SpriteBatch spriteBatch)
{
for (x = (int)Width - 1; x >= 0; x--)
{
spriteBatch.Draw(Pixel, new Rectangle((int)Position.X + x, (int)Position.Y - Elevation[x], 1, (int)Height), Color.White);
}
}
}
}

Answer 1

The problem is with your elevation() method. You are using y as your inner loop indexer and also assigning a value to it within the loop. So the loop starts, y is assigned a random value. As it continues the loop, it is decremented and then tested for being >=0. The only time this loop will exit is if y is assigned the random number of 0. So that is why all your Elevation are zero.
I am a little confused as to why you think you need an inner loop. Try:
public void elevation()
{
for (x = (int)Width - 1; x >= 0; x--)
{
Elevation[x] = rand.Next((int)MaxElevation);
}
}