/** 
 * Read in from the command line and
 * replace all lowercase letters with uppercase letters
 * This demonstrates how we can interact with characters as numbers and as characters.
 * 
 * flex -o upper.yy.c upper.yy
 * gcc -o upper upper.yy.c -ll
 */

/* This is a definition.*/
LOWER       [a-z]

%%

{LOWER}         printf("%c", yytext[0]+('A'-'a') );  /* we use the definition here for pattern-matching */
.                       printf("%s", yytext ); /* skip all other input */

%%
int main( int argc, char *argv[] ) {
		        
    yylex(); // a function of flex that read input till it is exhausted
    return 0;
}