Open In App
Related Articles

Lex Program to accept string starting with vowel

Improve
Improve
Improve
Like Article
Like
Save Article
Save
Report issue
Report
Lex is a computer program that generates lexical analyzers. Lex reads an input stream specifying the lexical analyzer and outputs source code implementing the lexer in the C programming language. The commands for executing the lex program are:
lex abc.l (abc is the file name)
cc lex.yy.c -efl
./a.out 
Let’s see lex program to accept string starting with vowel. Examples:
Input: animal
Output: Accepted

Input: zebra
Output: Not Accepted 
Below is the implementation:
/* Lex Program to accept string starting with vowel */
% {
  int flag = 0;
% }
  
%%
  
[aeiouAEIOU].[a-zA-Z0-9.]+ flag=1;
[a-zA-Z0-9]+
  
%%
  
main()
{
 yylex();
 if (flag == 1) 
    printf("Accepted"); 
 else
    printf("Not Accepted"); 
}

                    
Output:

Last Updated : 30 Sep, 2022
Like Article
Save Article
Previous
Next
Share your thoughts in the comments
Similar Reads