#include <stdio.h>  /* printf() */


void reverse( char str[] )
{
	char * ptr = str;

	while( ptr && *ptr )
		ptr++;

	for( ptr--; str < ptr; str++, ptr-- )
	{
		*str = *str ^ *ptr;
		*ptr = *str ^ *ptr;
		*str = *str ^ *ptr;
	}
}


int main( void )
{
	char txt[] = "O rato roeu a roupa do rei de Roma";

	reverse( txt );

	printf("%s\n", txt );

	return 0;
}

/* eof */