what is difference between c and embedded c
I've dabbled in embedded C about a year ago. I'm mostly a hardware guy so take my answer in that light.
I found it to be the same as normal C, but where you will find the largest difference is that you will be making use of commands that are specific to the brand of micro-controller you are using. These will likely be commands that are completely new to you. If you do not have knowledge of how a micro-controller works, you will need to take some time to learn this. Embedded is a world where the programs you write are intimately tied to the electronic hardware so some electronics engineering background will help you.