DFA that accepts either ab or ba as substring?

[shivajikobardan]

Homework Statement:

I need to create a DFA that contains substrings either ab or ba

Relevant Equations:

Deterministic finite automata no equations

Attempt at solution-:

Now this dfa will also accept abba which in my inituition it should not accept. But it does accept it. What is going here? Please guide

 

[lewando]

The English language statement "contains either the substrings ab or ba" is the issue. If you read this as an "inclusive or" then your DFA looks okay. If you read it as an "exclusive or" then it is not okay. Since you are a student and you recognize this potential ambiguity, figure out the "exclusive or" case. Submit both variations and your professor will be delighted!

Is the alphabet { a, b } ?