LEX Code that accepts the string with 0 only
In this article, we will discuss the overview of the LEX Code that accepts the string with 0 only. And will implement with LEX code also, we will understand the approach. Let’s discuss it one by one.
Problem Overview :
LEX Code that accepts the string with 0 only.
Input : 00 Output : Accepted Input : 1000 Output : Invalid Input : 23ab Output : Invalid Input : ab345 Output : Invalid Input : 00000 Output : Accepted
LEX provides us with an INITIAL state by default. So to make a DFA, use this as the initial state of the DFA. We define two more states: A, and DEAD, where the DEAD state would be used if encountering a wrong or invalid input. When the user inputs an invalid character, move to DEAD state, and then print “Invalid”. If the input string ends at A then display the message “Accepted”. Else if the input string ends at state INITIAL then displays the message “Not Accepted”.
To compile the lex program we need to have a Unix system that has flex installed into it. Then we need to save the file with the .l extension.
Then after saving the program closes the lex file and then open the terminal and write the following commands as follows.
lex filename.l cc lex.yy.c ./a.out
LEX Code :