.
| DFA | NFA |
|---|---|
It is called deterministic finite automata |
It is called non-deterministic finite automata |
For Every symbol of the alphabet, there is only one state transition in DFA. |
We do not need to specify how does the NFA react according to some symbol. |
DFA cannot use Empty String transition. |
NFA can use Empty String transition. |
| DFA can be understood as one machine. | NFA can be understood as multiple little machines computing at the same time. |
| DFA will reject the string if it end at other than accepting state. | If all of the branches of NFA dies or rejects the string, we can say that NFA reject the string. |
Backtracking is allowed in DFA. |
Backtracking is not always allowed in NFA. |
DFA is more difficult to construct. |
NFA is easier to construct. |