lex program to convert lower case letter of given file to upper case

%{

#include<stdio.h>

%}

%%

 /*** Rules section ***/

[a-z] printf("%c",yytext[0] - ('a' - 'A'));

0 { return 0;}

%%

int main()

{

  FILE *fp;

  fp = fopen("test.txt", "r");

  if (fp == NULL) { printf("File not found"); }

  yyin = fp;

  yylex();

  return 0;

}

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