What happens when I erase my stolen Iphone?

Basically my iphone was stolen 2 days ago.
Only my contacts were backed up on my iCloud.
I want to delete everything from my phone so if the thief does gain access, all my photos and stuff will be gone. But if i erase the iphone, will my contacts also be deleted and no longer backed up on iCloud?

You don't worry the thief doesn't know you unlock code. But you should report to police as soon as possible. It is possible to locate your phone with their help. But you should know your phone's IMEI number of stolen iphone.

No if your information is located in the cloud it will stay in the cloud. If you have an app called FIndmy phone or something like that. You can access it from a computer and locate your phone that is hooked up to that icloud account and delete all the information that is on the phone. No it will not delete your icloud info as far as i know only what is on that phone and completely erase everything on it so they can't use it.

Have you turn on "Find my Phone"? If you do, you can locate your phone position.
If you worry your contact will be deleted from iCloud, you can export your contacts from iCloud with some software. http://www.datarecoveryforiphone.com/ios-data-recovery.html