Will restoring my iPhone delete my contacts?

Mikey

Whatsapp contacts - if they're onnm contacts am I on theirs? I have the phone number of an old friend stored on my iPhone and they also show on my whatsapp contact list… Does this mean that they still have my phone number stored in their phone and also have whatsapp installed on their phone? The chat thing says they haven't been seen since 28th sept? If they didn't have my number on their phone would they still show as one of my contacts on whatsapp?
Restoring iphone, but keeping apps and contacts? It was getting a bit slow, and I want to restore it so its clean and fresh. My contacts are synced through icloud, so how will I get them back when the phone is restored? also, my apps will still be in itunes so I can resync them as well correct?
Restoring IPhone 4, want to keep photos and contacts? I have to restore my IPhone 4 due to the capacity of "other" taking up half the space on my phone. Unfortunately, I'm only 15 and I really don't know what I'm doing. I can live without saving my notes and text messages and such, but i would really like to save my photos and contacts. What is a simple way I can do this?
Quick! Does restoring my iPhone delete everything? Well I tried updating my iPhone but it came up with this error message and said that I needed to restore my iPhone if I want to carry on using it. The thing is, I have so much music on my iPhone. If I restore it, will it wipe everything off iTunes aswell or just my phone? Cream: 'ye' to what?