how to install Lex and Yacc in Ubuntu?

I am doing project in SENSE, for that i have to install Lex and Yacc. If you can help me how to install in Ubuntu. I very new to this area. So can you help me. Any website to study the basic of Lex and Yacc

Use the synaptic packet manager in order to install yacc / lex. If you are feeling more comfortable doing this on the console just do:

sudo apt-get install bison flex

There are some very nice articles on the net on how to get started with those tools. I found the article from CodeProject to be quite good and helpful (see here). But you should just try and search for "introduction to lex", there are plenty of good articles showing up.