Enhanced "for" Statements

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∟Enhanced "for" Statements

This section describes enhanced 'for' statement, which is a looping statement that executes the contained statement repeatedly for each element in a given list.

What Is Enhanced "for" Statement? - An enhanced "for" statement is a looping statement that executes the contained statement repeatedly for each element in a given list.

Here is the syntax for an enhanced "for" statement.

for (type e: list) contained_statement

When an enhanced "for" statement is executed, the flow of control can be described as:

Step 1. Declare a local variable "e".

Step 2. Verify if the "list" has next element.

Step 3. Assign the next element from the "list" to "e", if next element exists.

Step 4. End the "for" statement, if there is no next element.

Step 5. Run "contained_statement".

Step 6. Go back to Step 2.

Note that the "list" can be an array object, or an "Iterable" object. Here is a sample program that shows you how to use enhanced "for" statements:

/* EnhancedForStatementTest.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.util.*;
class EnhancedForStatementTest {
   public static void main(String[] arg) {
      java.io.PrintStream out = System.out;
      int max = 20;
      int sum = 0;

      out.println("Enhanced \"for\" statement on an array object:");
      Integer[] arrayList = { 1, 2, 3, 4, 5, 6, 7, 8, 9,10,
                             11,12,13,14,15,16,17,18,19,20};
      for (Integer i :  arrayList) sum += i;
      out.println("   Sum of 1 to 20: "+sum);
      sum = 0;

      out.println("Enhanced \"for\" statement on an iterable object:");
      Iterable<Integer> iterableList = Arrays.<Integer>asList(arrayList);
      for (Integer i :  iterableList) sum += i;
      out.println("   Sum of 1 to 20: "+sum);
      sum = 0;
   }
}

If you compile and run the above program, you will see:

herong> java EnhancedForStatementTest.java

Enhanced "for" statement on an array object:
   Sum of 1 to 20: 210

Enhanced "for" statement on an iterable object:
   Sum of 1 to 20: 210