Deterministic Finite Automaton (DFA) Solved Example

11. Design DFA for a language L= {w | length of w is multiple of 3) over Σ={a,b}

DFA M11 is = (Q, Σ, δ, q0, F)

Where

  1. Q : {q0, q1, q2}
  2. Σ : {a, b}
  3. δ = Q × Σ -> Q =
    • δ(q0, a) = q1
    • δ(q0, b) = q1
    • δ(q1, a) = q2
    • δ(q1, b) = q2
    • δ(q2, a) = q0
    • δ(q2, b) = q0
    •  
  1. q0 : q0.
  2. F : {q0}

 

Note: The transition function can also be described with a transition table.

12. Design DFA for a language L= {w | w is an empty string or a string that ends with 1) over Σ={0,1}

DFA M12 is = (Q, Σ, δ, q0, F)

Where

  1. Q : {q0, q1}
  2. Σ : {0, 1}
  3. δ = Q × Σ -> Q =
    • δ(q0, 0) = q0
    • δ(q0, 1) = q1
    • δ(q1, 0) = q0
    • δ(q1, 1) = q1
  1. q0 : q0.
  2. F : {q0}

 

Note: The transition function can also be described with a transition table.

13. Design DFA for a language L= {w | contains neither 00 nor 11) over Σ={0,1}

DFA M13 is = (Q, Σ, δ, q0, F)

Where

  1. Q : {q0, q1,q2,q3}
  2. Σ : {0, 1}
  3. δ = Q × Σ -> Q =
    • δ(q0, 0) = q2
    • δ(q0, 1) = q1
    • δ(q1, 0) = q2
    • δ(q1, 1) = q3
    • δ(q2, 0) = q3
    • δ(q2, 1) = q1
    • δ(q3, 0) = q3
    • δ(q3, 1) = q3
  1. q0 : q0.
  2. F : {q1.q2}

 

Note: The transition function can also be described with a transition table.

14. Design DFA that accepts odd binary numbers. over Σ={0,1}

DFA M14 is = (Q, Σ, δ, q0, F)

Where

  1. Q : {q0, q1,q2,q3}
  2. Σ : {0, 1}
  3. δ = Q × Σ -> Q =
    • δ(q0, 0) = q3
    • δ(q0, 1) = q1
    • δ(q1, 0) = q2
    • δ(q1, 1) = q1
    • δ(q2, 0) = q2
    • δ(q2, 1) = q1
    • δ(q3, 0) = q3
    • δ(q3, 1) = q3
  1. q0 : q0.
  2. F : {q1}

 

Note: The transition function can also be described with a transition table.