How to use array in cg shader

I want to use array in my shader.

I know how to pass value:

shaderMat.SetFloat("_Sample0", 150);

In my shader, I have declared:

uniform float _Sample[2];

But when I try to access the values as _Sample[0] or _Sample[1] it doesnt work. It seems all indexes has value 0 in them no matter what I do.

Please, any ideas?

Thanks

Well you could create a texture in code using [0,1] to represent data then passing the texture.
Using it as a array storage.
There really is no simple array type.