Merge pull request #266 from javaistic/dev

arghyaxcodes · web-flow · commit e3d4c8148ee8 · 2022-06-07T16:35:51.000+05:30
Add Java for-each Loop docs
diff --git a/src/navs/documentation.js b/src/navs/documentation.js
@@ -18,5 +18,10 @@ export const documentationNav = {
     pages['expressions-statements-blocks'],
     pages['comments'],
   ],
-  'Java Flow Control': [pages['if-else-statement'], pages['switch-statement'], pages['for-loop']],
+  'Java Flow Control': [
+    pages['if-else-statement'],
+    pages['switch-statement'],
+    pages['for-loop'],
+    pages['enhanced-for-loop'],
+  ],
 }
diff --git a/src/pages/docs/enhanced-for-loop.mdx b/src/pages/docs/enhanced-for-loop.mdx
@@ -0,0 +1,157 @@
+---
+title: Java for-each Loop
+description: In this tutorial, we will learn about the Java for-each loop and its difference with for loop with the help of examples.
+---
+
+In Java, the **for-each loop** is used to iterate through elements of [arrays](/docs/arrays) and collections (like [ArrayList](/docs/arraylist)). It is also known as the enhanced for loop.
+
+## `for-each` Loop Syntax
+The syntax of the Java **for-each** loop is:
+
+```java
+for(dataType item : array) {
+    ...
+}
+```
+Here,
+
+- **array** - an array or a collection
+- **item** - each item of array/collection is assigned to this variable
+- **dataType** - the data type of the array/collection
+
+### Example 1: Print Array Elements
+
+#### Input
+
+```java
+// print array elements
+
+class Main {
+  public static void main(String[] args) {
+
+    // create an array
+    int[] numbers = {3, 9, 5, -5};
+
+    // for each loop
+    for (int number: numbers) {
+      System.out.println(number);
+    }
+  }
+}
+```
+#### Output
+
+```text
+3
+9
+5
+-5
+```
+Here, we have used the **for-each loop** to print each element of the numbers array one by one.
+
+- In the first iteration, the item will be 3.
+- In the second iteration, the item will be 9.
+- In the third iteration, the item will be 5.
+- In the fourth iteration, the item will be -5.
+
+### Example 2: Sum of Array Elements
+
+#### Input
+
+```java
+// Calculate the sum of all elements of an array
+
+class Main {
+ public static void main(String[] args) {
+
+   // an array of numbers
+   int[] numbers = {3, 4, 5, -5, 0, 12};
+   int sum = 0;
+
+   // iterating through each element of the array
+   for (int number: numbers) {
+     sum += number;
+   }
+
+   System.out.println("Sum = " + sum);
+ }
+}
+```
+#### Output:
+
+```text
+Sum = 19
+```
+
+In the above program, the execution of the for-each loop looks as:
+
+| Iteration |	Variables |
+|----------|----------|
+|1|	`number` = 3  `sum` = 0 + 3 = 3|
+|2|	`number` = 4  `sum` = 3 + 4 = 7
+|3|	`number` = 5  `sum` = 7 + 5 = 12|
+|4|	`number` = -5  `sum` = 12 + (-5) = 7|
+|5|	`number` = 0  `sum` = 7 + 0 = 7|
+|6| `number` = 12  `sum` = 7 + 12 = 19|
+
+As we can see, we have added each element of the `numbers` array to the `sum` variable in each iteration of the loop.
+
+## for loop Vs for-each loop
+
+Let's see how a for-each loop is different from a regular [Java for loop](/docs/for-loop).
+
+### 1. Using for loop
+
+#### Input
+
+```java
+class Main {
+ public static void main(String[] args) {
+
+   char[] vowels = {'a', 'e', 'i', 'o', 'u'};
+
+   // iterating through an array using a for loop
+   for (int i = 0; i < vowels.length; ++ i) {
+     System.out.println(vowels[i]);
+   }
+ }
+}
+```
+#### Output:
+
+```text
+a
+e
+i
+o
+u
+```
+### 2. Using for-each Loop
+
+#### Input
+
+```java
+class Main {
+ public static void main(String[] args) {
+
+   char[] vowels = {'a', 'e', 'i', 'o', 'u'};
+
+   // iterating through an array using the for-each loop
+   for (char item: vowels) {
+     System.out.println(item);
+   }
+ }
+}
+```
+#### Output:
+
+```text
+a
+e
+i
+o
+u
+```
+Here, the output of both programs is the same. However, the **for-each** loop is easier to write and understand.
+
+This is why the **for-each** loop is preferred over the **for** loop when working with arrays and collections.
