initializationOpt.cpp

#include <iostream>
#include <iomanip>
#include <cstdlib>

/** try with -O0 then -O3 **/
struct foo
{
   /**
    * remember, this should be undetermined....
    * never leave a class var like this
    */
   bool x;
};

int
main( int argc, char **argv )
{
    foo f;
    /** 
     * compiler seems to optimize this to f.x always true
     * unless we add default initialization explicitely for
     * x or else to set, but you shouldn't rely on this...
     * in fact, NEVER rely on this.
     */
    if( argc == 2 )
    {
      f.x = true; 
    }

    std::cout << std::boolalpha << f.x << "\n";
    return( EXIT_SUCCESS );
}