@protocol P @end @interface NSMutableArray - (id)objectAtIndexedSubscript:(unsigned int)index; - (void)setObject:(id)object atIndexedSubscript:(unsigned int)index; @end @interface NSMutableDictionary - (id)objectForKeyedSubscript:(id)key; - (void)setObject:(id)object forKeyedSubscript:(id)key; @end void all(void) { NSMutableArray *array; id oldObject = array[10]; array[10] = oldObject; NSMutableDictionary *dictionary; id key; id newObject; oldObject = dictionary[key]; dictionary[key] = newObject; }