Difference between Time-sharing computers and computers which use Round Robin scheduling algorithm? So maybe I'm confused in these concepts 

but i thought that time sharing computer is a computer which the processor switches between different processes quickly to achieve a good response time 

but isn't this the same as Round Robin algorithm?! i mean aren't we scheduling between different processes   in Time sharing computer just like Round robin? or am i missing something here? what is the difference?
No, they are not equivalent, but you are right to note a similarity.

Yes, a time sharing computer is one in which the computer switches between different processes.  The schedular is the part of the operating system that determines when to switch between processes, and which process to switch to.   A round robin scheduler is one particular type of scheduling strategy that could be used in a time sharing computer, but there are other possible scheduling strategies as well.