I want to make simple online IDE with cloud storage feature, let us say this should be implement in C++,Python ,etc...  
Does it SaaS (I mean the IDE :-) ) ?
I'm new in SaaS and Cloud world , where to start to make something like what I said above ?
Thanks.
Based on Wikipedia:

Software as a service (SaaS) is a software licensing and delivery
  model in which software is licensed on a subscription basis and is
  centrally hosted

There are many implementations of SaaS. Such as ERP, CRM, CMS, etc. Find out by your self what kind of service will you offer to your customers. Then choose the right SaaS implementation.
Integrated Development Environment with SaaS