%{
#include <stdio.h>
%}
 
INTEGER [+-]?[0-9]+
FLOAT [+-]?([0-9]*\.[0-9]+|[0-9]+\.[0-9]*)(([eE][+-]?[0-9]+)?)
CONSTANT ({INTEGER}|{FLOAT})
 
%%
 
^{CONSTANT}$ {
    printf("✅ The string '%s' is a valid constant.\n", yytext);
}
 
.*\n {
    yytext[yyleng-1] = '\0';
    printf("❌ The string '%s' is NOT a constant.\n", yytext);
}
 
%%
 
int main() {
    printf("Enter a string to check (Ctrl+D to exit):\n");
    yylex();
    return 0;
}
 
int yywrap() {
    return 1;
}

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