Java · Theory

For-Each Loop in Java

Theory

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For-Each Loop in Java

for-each (enhanced for) walks every element without an index. Read it as “for each item in this list”. Shape: for (int x : arr) System.out.println(x);

Use it when you only need values. If you need the position, or you must replace an item by index, use a normal for with i.

Do not remove items from a list inside for-each without an iterator — Java can throw ConcurrentModificationException. Keep for-each simple: read and print, or copy.

Let's take this on the board with one tiny Main class — no extra files. For-Each Loop in Java — output: 10 then 20 then 30. for-each walks the array — no index variable. Start from main, go line by line, and stop at each print. That output is the proof for For-Each Loop.

Exam tip

Say when for-each is better than index-for, and when it is not.

Example

// For-Each Loop
public class Main {
  public static void main(String[] args) {
    int[] nums = {10, 20, 30};
    for (int x : nums) {
      System.out.println(x);
    }
  }
}

For-Each Loop in Java — output: 10 then 20 then 30. for-each walks the array — no index variable.

Short notes

Deffor-each walks every element without an index.
Rulefor (Type x : arr). Read as “for each item”.
UseOnly values, not positions.
TrapRemoving from a list inside for-each can crash.

Java · Theory

For-Each Loop in Java

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Theory

19/270

For-Each Loop in Java

for-each (enhanced for) walks every element without an index. Read it as “for each item in this list”. Shape: for (int x : arr) System.out.println(x);

Use it when you only need values. If you need the position, or you must replace an item by index, use a normal for with i.

Do not remove items from a list inside for-each without an iterator — Java can throw ConcurrentModificationException. Keep for-each simple: read and print, or copy.

Exam tip

Say when for-each is better than index-for, and when it is not.

Example

// For-Each Loop
public class Main {
  public static void main(String[] args) {
    int[] nums = {10, 20, 30};
    for (int x : nums) {
      System.out.println(x);
    }
  }
}

For-Each Loop in Java — output: 10 then 20 then 30. for-each walks the array — no index variable.

Short notes

Deffor-each walks every element without an index.
Rulefor (Type x : arr). Read as “for each item”.
UseOnly values, not positions.
TrapRemoving from a list inside for-each can crash.

For-Each Loop in Java

Example

Short notes

Questions

For-Each Loop in Java

Example

Short notes

Questions