lex program to check whether Date entered by user in format (dd/mm/yyyy) is valid or not

%{

#include<stdio.h>

%}

%%

((0[1-9])|([1-2][0-9])|(3[0-1]))\/((0[1-9])|(1[0-2]))\/(19[0-9]{2}|2[0-9]{3}) printf("Valid");

.* printf("Invalid");

%%

int main()

{

 yylex();

 return 0;

}

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