#include <stdio.h>

void func( double r )
{  

   {  /* Start of a new scope */

      /* NOTE: without this inner scope, you will get error:
               'r' redeclared !!!                                */

      printf( "1. r = %lf\n", r );         /* Access parameter r */


      double r = 4.444;                    /* (1) */

      printf( "2. r = %lf\n", r );         /* Access r(1) */
   }
}

int main( int argc, char* argv[] )
{  
   func( 3.14 );                        // Pass 3.14 into parameter variable r

}