Write a LEX program to check whether input symbol is number or character.

            

               Code :

%{

%}

%%

[0-9] {printf("Input is a number");}

[A-Za-z] {printf("Input is a character");}

%%

main()

{

     yylex();

}

int yywrap()

{

     return 1;

}

Write a LEX program to check whether input is multidigit number or string.

              

               Code :

%{

%}

%%

[0-9][0-9]+ {printf("Input is a multi digit number");}

[A-Za-z][A-Za-z]+ {printf("Input is a multi character");}

%%

main()

{

     yylex();

}

int yywrap()

{

     return 1;

}

Write a LEX program to check whether inputted character is vowel or not.

            

               Code :

%{

%}

%%

[aeiouAEIOU]              {printf("Input is a vowel");}

[A-Za-z(^aeiouAEIOU)]     {printf("Input is not a vowel");}

%%

main()

{

     yylex();

}

int yywrap()

{

     return 1;

}

Write a LEX program to count only those words that start with vowels.

              

               Code :

%{

%}

%%

[aeiouAEIOU][A-Za-z]+              {printf("Word starting with vowel");}

[A-Za-z(^aeiouAEIOU)][A-Za-z]+      {printf("Word not starting with vowel");}

%%

main()

{

     yylex();

}

int yywrap()

{

     return 1;

}

Write a LEX program to count number of vowels from all inputted symbols.

              

               Code :

%{           

     int count_v;

%}

%%

[aeiouAEIOU]           {count_v++;}

%%

main()

{

     yylex();

     printf("Count of vowels= %d\n",count_v);

}

int yywrap()

{

     return 1;

}