changing component variables

I was wondering how to change a variable for example I have a collider that I want to increase it's radius over time I have tried

gameObject.collider.radius++;

but I get an error Expression cannot be assigned to --- please help

You can't use `++` in this particular case, but you can use `+= 1`.

use this syntax to access the component:

(*Component_Type*)gameObject.GetComponent("*Component_Type*")