%{
#include <stdio.h>
int number_count = 0;
%}

%%
[0-9]+(\.[0-9]+)? { number_count++; }
.|\n {}
%%

int main() {
    printf("Enter a string: ");
    yylex();
    printf("\nTotal numbers found: %d\n", number_count);
    return 0;
}
int yywrap() {
    return 1;
}

Standard output is empty

ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: Can't ignore goal at this port
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: No previous search
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Can't ignore goal at this port
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ?    Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ?    Exception: (3) program ?    Call: (3) program ? ERROR: Unknown option (h for help)
   Call: (3) program ?    Exit: (3) program ? [Could not find retry-point]
% Execution Aborted
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit