ITSC 1213 - Introduction to CS 2 How to Design Programs with Object Oriented Programming

There is a special kind of loop that can be used with arrays that is called an enhanced for loop or a for each loop. This loop is much easier to write because it does not involve an index variable or the use of the []. It just sets up a variable that is set to each value in the array successively.

To set up a for-each loop, use for (type variable : arrayname) where the type is the type for elements in the array, and read it as “for each variable value in arrayname”.

See the examples below in Java that loop through an int and a String array. Notice the type of the loop variable is the type of the array.

int[] highScores = { 10, 9, 8, 8};
String[] names = {"Jamal", "Emily", "Destiny", "Mateo"};
// for each loop: for each value in highScores
// for (type variable : arrayname)
for (int value : highScores)
{
    // Notice no index or [ ], just the variable value!
    System.out.println( value );
}
// for each loop with a String array to print each name
// the type for variable name is String!
for (String name : names)
{
    System.out.println(name);
}

Use the enhanced for each loop with arrays whenever you can, because it cuts down on errors. You can use it whenever you need to loop through all the elements of an array and don’t need to know their index and don’t need to change their values. It starts with the first item in the array (the one at index 0) and continues through in order to the last item in the array. This type of loop can only be used with arrays and some other collections of items like ArrayLists.

I: If you wish to access every element of an array.
II: If you wish to modify elements of the array.
III: If you wish to refer to elements through a variable name instead of an array index.

int[ ] numbers = {44, 33, 22, 11};
for (int num : numbers)
{
    num *= 2;
}
for (int num : numbers)
{
    System.out.print(num + " ");
}

public int getLargest()
{
---
  int largest = vals[0];
---
  for (int item : vals)
  {
---
    if (item > largest)
    {
---
      largest = item;
---
    }  // end if
---
  } // end for
  return largest;
---
} // end method

boolean temp = false;
for (int val : array)
{
  temp = ( target == val );
}
return temp;

Practice