classification tables

Dear R-users

I have two vectors. One vector includes true values and the other vector has 
estimated values. Values are all integers from 1 to 4.

For example,

x <- c(1,2,3,4,2,3,3,1,2,3)
y <- c(2,1,3,4,1,3,3,2,2,3)

I would like to a classfication table x by y. With the table, I would like 
to calculate what percentage is correct classfication.

Which R function do I need to use for creating a 4 * 4 classification table?

Thank you.

Taka,