Context formal language recognizing even number of 0's and odd number of 1's
This language is, in fact, regular&nbsp;&ndash; it is accepted by an automaton with just four states. I suggest that you first figure out what this automaton is and use what you learn to figure out a grammar. In particular, you don't need any context-free "tricks" or techniques.

If you need to, mouse-over the yellow area below to see a more detailed hint for the automaton.


   Think about what data you need to know when you reach the end of the string, in order to decide if your input is in the language. What is the value of that data when you haven't read any input? How do you update that data as you read the input?