Java foreach using reference to replace items won't work -

in exercice must replace object within loop. solution use "listiterator". colleague try use foreach syntax , play reference solution won't work.

// doesn't work ( growable growable : growables ) {   growable = growable.grow(); // return object (seed -> sprout, ..) }  // (final listiterator<growable> = growables.listiterator(); it.hasnext();) {   it.set(it.next().grow()); } 

from documentation[1], can read foreach not suitable replacement because don't have reference iterator.

the program needs access iterator in order remove current element. for-each loop hides iterator, cannot call remove. therefore, for-each loop not usable filtering. not usable loops need replace elements in list or array traverse it.

but have reference iterated object. wrong ? can explain me why "foreach" solution isn't working ?

thanks

[1] http://docs.oracle.com/javase/1.5.0/docs/guide/language/foreach.html

in first snippet, take element growables , assign growable. means variable growable references element.

if reassign growable, starts referencing object. doesn't change object growables.

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to understand what's going on, compare array. using foreach syntax:

int[] array = {1, 2, 3}; (int x : array) {     x = 0; } system.out.println(array[0]); 

this print 1. reason snippet equivalent to

int[] array = {1, 2, 3}; (int = 0; < array.length; i++) {     int x = array[i];     x = 0; } system.out.println(array[0]); 

now it's more obvious assignment x not modify array.